ORGANIC LIGHT-EMITTING DEVICE

Abstract

An organic light-emitting device including: a first electrode; a second electrode; and an organic layer including an emission layer between the first electrode and the second electrode. The organic layer may include at least one compound selected from a first compound and a second compound, in addition to a third compound. The first compound is represented by one selected from Formulae 1-1 and 1-2, the second compound is represented by Formula 2, and the third compound is represented by one selected from Formulae 3-1A and 3-2A: ##STR00001##

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0149727, filed on Oct. 27, 2015, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.

BACKGROUND

[0002] 1. Field

[0003] One or more aspects of example embodiments of the present disclosure are related to an organic light-emitting device.

[0004] 2. Description of the Related Art

[0005] Organic light emitting devices are self-emission devices that have wide viewing angles, high contrast ratios, short response times, and/or excellent brightness, driving voltage, and/or response speed characteristics, and may produce full-color images.

[0006] An organic light-emitting device may include a first electrode on a substrate, and a hole transport region, an emission layer, an electron transport region, and a second electrode sequentially positioned on the first electrode. Holes provided from the first electrode may move toward the emission layer through the hole transport region, and electrons provided from the second electrode may move toward the emission layer through the electron transport region.

[0007] Carriers (such as holes and electrons) may recombine in the emission layer to produce excitons. These excitons may transition (e.g., radiatively decay) from an excited state to the ground state to thereby generate light.

SUMMARY

[0008] One or more aspects of example embodiments of the present disclosure are directed toward an organic light-emitting device having high efficiency and a long lifespan.

[0009] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented example embodiments.

[0010] One or more example embodiments of the present disclosure provide an organic light-emitting device including:

[0011] a first electrode;

[0012] a second electrode; and

[0013] an organic layer including an emission layer between the first electrode and the second electrode,

[0014] the organic layer including at least one compound selected from a first compound and a second compound; in addition to a third compound,

[0015] wherein the first compound is represented by one selected from Formulae 1-1 and 1-2, the second compound is represented by Formula 2, and the third compound is represented by one selected from Formulae 3-1A and 3-2A:

##STR00002##

[0016] In Formulae 1-1, 1-2, 2, 3-1, and 3-2,

[0017] A.sub.11 to A.sub.13, A.sub.21 to A.sub.24, and A.sub.31 to A.sub.34 may each independently be selected from a C.sub.5-C.sub.20 carbocyclic group and a C.sub.1-C.sub.20 heterocyclic group,

[0018] X.sub.11 may be selected from N[(L.sub.11).sub.a11-Ar.sub.11], C(Ar.sub.13)(Ar.sub.15), oxygen (O), and sulfur (S),

[0019] X.sub.12 may be selected from N[(L.sub.12).sub.a12-Ar.sub.12], C(Ar.sub.14)(Ar.sub.16), O, and S,

[0020] X.sub.21 may be selected from N[(L.sub.22).sub.a22-Ar.sub.22], C(Ar.sub.23)(Ar.sub.24), O, S, Si(Ar.sub.25)(Ar.sub.26), P[(L.sub.23).sub.a23-Ar.sub.27], B[(L.sub.24).sub.a24-Ar.sub.28], and P(.dbd.O)[(L.sub.25).sub.a25-Ar.sub.29],

[0021] L.sub.11, L.sub.12, L.sub.21 to L.sub.26, and L.sub.31 to L.sub.35 may each independently be selected from a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkylene group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkylene group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenylene group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenylene group, a substituted or unsubstituted C.sub.6-C.sub.60 arylene group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group,

[0022] a11, a12, a21 to a26, and a31 to a35 may each independently be an integer selected from 0 to 5,

[0023] Ar.sub.11 to Ar.sub.16, Ar.sub.21 to Ar.sub.29, and Ar.sub.31 to Ar.sub.35 may each independently be a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5), and --B(Q.sub.6)(Q.sub.7), provided that:

[0024] in Formula 3-1A, Ar.sub.31 and Ar.sub.32 are both not a substituted or unsubstituted fluorenyl group,

[0025] in Formula 2, Ar.sub.25 and Ar.sub.26 may optionally be linked to each other to form a saturated or unsaturated ring,

[0026] in Formulae 3-1A and 3-2A, Ar.sub.31 and Ar.sub.32 may optionally be linked to each other to form a saturated or unsaturated ring, and

[0027] in Formula 3-2A, Ar.sub.33 and Ar.sub.34 may optionally be linked to each other to form a saturated or unsaturated ring,

[0028] R.sub.11 to R.sub.13, R.sub.21 to R.sub.24, and R.sub.31 to R.sub.34 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, --Si(Q.sub.11)(Q.sub.12)(Q.sub.13), --N(Q.sub.14)(Q.sub.15), and --B(Q.sub.16)(Q.sub.17),

[0029] b11 to b13, b21 to b24, and b31 to b34 may each independently be an integer selected from 0 to 8,

[0030] c1 to c5 may each independently be an integer selected from 1 to 3, and

[0031] at least one substituent of the substituted C.sub.3-C.sub.10 cycloalkylene group, substituted C.sub.1-C.sub.10 heterocycloalkylene group, substituted C.sub.3-C.sub.10 cycloalkenylene group, substituted C.sub.1-C.sub.10 heterocycloalkenylene group, substituted C.sub.6-C.sub.60 arylene group, substituted C.sub.1-C.sub.60 heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C.sub.1-C.sub.60 alkyl group, substituted C.sub.2-C.sub.60 alkenyl group, substituted C.sub.2-C.sub.60 alkynyl group, substituted C.sub.1-C.sub.60 alkoxy group, substituted C.sub.3-C.sub.10 cycloalkyl group, substituted C.sub.1-C.sub.10 heterocycloalkyl group, substituted C.sub.3-C.sub.1 cycloalkenyl group, substituted C.sub.1-C.sub.10 heterocycloalkenyl group, substituted C.sub.6-C.sub.60 aryl group, substituted C.sub.6-C.sub.60 aryloxy group, substituted C.sub.6-C.sub.60 arylthio group, substituted C.sub.1-C.sub.60 heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from the group consisting of:

[0032] deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group;

[0033] a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, and a C.sub.1-C.sub.60 alkoxy group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --Si(Q.sub.21)(Q.sub.22)(Q.sub.23), --N(Q.sub.24)(Q.sub.25), and --B(Q.sub.26)(Q.sub.27);

[0034] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group;

[0035] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --Si(Q.sub.31)(Q.sub.32)(Q.sub.33), --N(Q.sub.34)(Q.sub.35), and --B(Q.sub.36)(Q.sub.37);

[0036] --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), --N(Q.sub.34)(Q.sub.35), and --B(Q.sub.46)(Q.sub.47),

[0037] wherein Q.sub.1 to Q.sub.7, Q.sub.11 to Q.sub.17, Q.sub.21 to Q.sub.27, Q.sub.31 to Q.sub.37, and Q.sub.41 to Q.sub.47 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group; and

[0038] a C.sub.6-C.sub.60 aryl group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.1-C.sub.60 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, and

[0039] Q.sub.4 and Q.sub.5 may optionally be linked to each other to form a saturated or unsaturated ring.

BRIEF DESCRIPTION OF THE DRAWING

[0040] These and/or other aspects will become apparent and more readily appreciated from the following description of the example embodiments, taken in conjunction with the drawing, which is a schematic view showing the structure of an organic light-emitting device according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0041] Reference will now be made in more detail to example embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout, and duplicative descriptions thereof may not be provided. In this regard, the present example embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the example embodiments are merely described below, by referring to the drawing, to explain aspects of the present description. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of", "one of", "selected from", "at least one selected from", and "one selected from", when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

[0042] In the drawings, the thicknesses of layers, films, panels, regions, etc., may be exaggerated for clarity. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening element(s) may also be present. In contrast, when an element is referred to as being "directly on" another element, no intervening elements are present.

[0043] The drawing is a schematic view showing the structure of an organic light-emitting device 10 according to an embodiment of the present disclosure. The organic light-emitting device 10 includes a first electrode 110, an organic layer 150, and a second electrode 190.

[0044] Hereinafter, the structure of an organic light-emitting device according to an embodiment of the present disclosure and a method of manufacturing an organic light-emitting device according to an embodiment of the present disclosure will be described in connection with the drawing.

[0045] In the drawing, a substrate may be under the first electrode 110 and/or above the second electrode 190. The substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and/or water-resistance.

[0046] The first electrode 110 may be formed by depositing and/or sputtering a material for forming the first electrode 110 on the substrate. When the first electrode 110 is an anode, the material for the first electrode 110 may be selected from materials with a high work function to facilitate hole injection. The first electrode 110 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming a first electrode may be a transparent and highly conductive material, and non-limiting examples of such a material may include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO.sub.2), and zinc oxide (ZnO). When the first electrode 110 is a semi-transmissive electrode or a reflective electrode, at least one selected from magnesium (Mg), aluminum (Al), aluminum-lithium (Al--Li), calcium (Ca), magnesium-indium (Mg--In), and magnesium-silver (Mg--Ag) may be used as a material for forming the first electrode 110.

[0047] The first electrode 110 may have a single-layer structure or a multi-layer structure including two or more layers. For example, the first electrode 110 may have a three-layered structure of ITO/Ag/ITO, but embodiments of the structure of the first electrode 110 are not limited thereto.

[0048] The organic layer 150 is on the first electrode 110, and the second electrode 150 may include an emission layer.

[0049] The organic layer may include at least one compound selected from a first compound and a second compound; in addition to a third compound,

[0050] wherein the first compound is represented by one selected from Formulae 1-1 and 1-2, the second compound is represented by Formula 2, and the third compound is represented by one selected from Formulae 3-1A and 3-2A:

##STR00003##

[0051] In Formulae 1-1, 1-2, 2, 3-1, and 3-2,

[0052] A.sub.11 to A.sub.13, A.sub.21 to A.sub.24, and A.sub.31 to A.sub.34 may each independently be selected from a C.sub.5-C.sub.20 carbocyclic group and a C.sub.1-C.sub.20 heterocyclic group.

[0053] For example, A.sub.11 to A.sub.13, A.sub.21 to A.sub.24, and A.sub.31 to A.sub.34 may each independently be selected from a benzene, a naphthalene, a phenanthrene, an anthracene, a pyridine, a pyrimidine, a quinoline, an isoquinoline, naphthyridine, a quinoxaline, a phthalazine, a quinazoline, and a cinnoline.

[0054] In one or more embodiments, A.sub.11 to A.sub.13 and A.sub.21 to A.sub.24 may each independently be selected from a benzene, a naphthalene, a phenanthrene, an anthracene, a pyridine, a pyrimidine, a quinoline, an isoquinoline, naphthyridine, a quinoxaline, a phthalazine, a quinazoline, and a cinnoline,

[0055] A.sub.31 to A.sub.34 may each independently be selected from a benzene, a naphthalene, a phenanthrene, and an anthracene, but embodiments of the present disclosure are not limited thereto.

[0056] In Formulae 1-1, 1-2, 2, 3-1, and 3-2,

[0057] X.sub.11 may be selected from N[(L.sub.11).sub.a11-Ar.sub.11], C(Ar.sub.13)(Ar.sub.15), oxygen (O), and sulfur (S),

[0058] X.sub.12 may be selected from N[(L.sub.12).sub.a12-Ar.sub.12], C(Ar.sub.14)(Ar.sub.16), O, and S, and

[0059] X.sub.21 may be selected from N[(L.sub.22).sub.a22-Ar.sub.22], C(Ar.sub.23)(Ar.sub.24), O, S, Si(Ar.sub.25)(Ar.sub.26), P[(L.sub.23).sub.a23-Ar.sub.27], B[(L.sub.24).sub.a24-Ar.sub.28], and P(.dbd.O)[(L.sub.25).sub.a25-Ar.sub.29].

[0060] For example, X.sub.11 may be N[(L.sub.11).sub.a11-Ar.sub.11] and X.sub.12 may be N[(L.sub.12).sub.a12-Ar.sub.12]; or

[0061] X.sub.11 may be N[(L.sub.11).sub.a11-Ar.sub.11] and X.sub.12 may be C(Ar.sub.14)(Ar.sub.16); or

[0062] X.sub.11 may be N[(L.sub.11).sub.a11-Ar.sub.11] and X.sub.12 may be O; or

[0063] X.sub.11 may be N[(L.sub.11).sub.a11-Ar.sub.11] and X.sub.12 may be S.

[0064] In Formulae 1-1, 1-2, 2, 3-1, and 3-2,

[0065] L.sub.11, L.sub.12, L.sub.21 to L.sub.26, and L.sub.31 to L.sub.35 may each independently be selected from a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkylene group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkylene group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenylene group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenylene group, a substituted or unsubstituted C.sub.6-C.sub.60 arylene group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group.

[0066] For example, L.sub.11, L.sub.12, and L.sub.21 to L.sub.26 may each independently be selected from the group consisting of:

[0067] a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, a benzofuranylene group, a benzothiophenylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a thiadiazolylene group, an imidazopyridinylene group, an imidazopyrimidinylene group; and

[0068] a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, a benzofuranylene group, a benzothiophenylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a thiadiazolylene group, an imidazopyridinylene group, and an imidazopyrimidinylene group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group,

[0069] L.sub.31 to L.sub.35 may each independently be selected from the group consisting of:

[0070] a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, a ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, a carbazolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group;

[0071] a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, a carbazolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, and a dibenzocarbazolylene group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, and a dibenzocarbazolyl group; and

[0072] a phenylene group substituted with at least one --N(Q.sub.44)(Q.sub.45), wherein Q.sub.44 and Q.sub.45 may each be the same as described above.

[0073] In one or more embodiments, L.sub.11, L.sub.12, and L.sub.21 to L.sub.26 may each independently be selected from groups represented by Formulae 3-1 to 3-34, and

[0074] L.sub.31 to L.sub.35 may each independently be selected from Formulae 3-1 to 3-10, 3-26 to 3-28, 3-32, and 3-33, but embodiments of the present disclosure are not limited thereto:

##STR00004## ##STR00005## ##STR00006## ##STR00007##

[0075] In Formulae 3-1 to 3-34,

[0076] Y.sub.11 may be selected from O, S, S(.dbd.O), S(.dbd.O).sub.2, C(Z.sub.3)(Z.sub.4), N(Z.sub.5), and Si(Z.sub.6)(Z.sub.7),

[0077] Z.sub.1 to Z.sub.7 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.2-C.sub.20 alkenyl group, a C.sub.2-C.sub.20 alkynyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and --N(Q.sub.44)(Q.sub.45),

[0078] d1 may be an integer selected from 1 to 4, d2 may be an integer selected from 1 to 3, d3 may be an integer selected from 1 to 6, d4 may be an integer selected from 1 to 8, d5 may be selected from 1 and 2, d6 may be an integer selected from 1 to 5, and * and *' may each indicate a binding site to neighboring atom.

[0079] a11, a12, a21 to a26, and a31 to a35 in Formulae 1-1, 1-2, 2, 3-1, and 3-2 may each independently be an integer selected from 0 to 5.

[0080] a11 indicates the number of L.sub.11 groups. When a11 is 0, -(L.sub.11).sub.a11- indicates a single bond, and when a11 is 2 or more, the 2 or more L.sub.11 groups may be identical to or different from each other. a12, a21 to a26, and a31 to a35 may each be the same as described herein in connection with a11 and Formulae 1-1, 1-2, 2, 3-1, and 3-2.

[0081] For example, a11, a12, a21 to a26, and a31 to a35 in Formulae 1-1, 1-2, 2, 3-1, and 3-2 may each independently be an integer selected from 0 to 3, but embodiments of the present disclosure are not limited thereto.

[0082] Ar.sub.11 to Ar.sub.16, Ar.sub.21 to Ar.sub.29, and Ar.sub.31 to Ar.sub.35 in Formulae 1-1, 1-2, 2, 3-1, and 3-2 may each independently be a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5), and --B(Q.sub.6)(Q.sub.7), provided that:

[0083] in Formula 3-1A, Ar.sub.31 and Ar.sub.32 are both not a substituted or unsubstituted fluorenyl group,

[0084] in Formula 2, Ar.sub.25 and Ar.sub.26 may optionally be linked to each other to form a saturated or unsaturated ring,

[0085] in Formulae 3-1A and 3-2A, Ar.sub.31 and Ar.sub.32 may optionally be linked to each other to form a saturated or unsaturated ring, and

[0086] in Formula 3-2A, Ar.sub.33 and Ar.sub.34 may optionally be linked to each other to form a saturated or unsaturated ring.

[0087] For example, Ar.sub.25 and Ar.sub.26 may optionally be linked to each other to form a carbocyclic ring.

[0088] In one or more embodiments, a31 and a32 may each be 0, and Ar.sub.31 and Ar.sub.32 may combine (e.g., couple) with the nitrogen atom to form a carbazole ring.

[0089] In one or more embodiments, a33 and a34 may each be 0, and Ar.sub.33 and Ar.sub.34 may combine (e.g., couple) with the nitrogen atom to form a carbazole ring.

[0090] Q.sub.1 to Q.sub.7 may each be the same as described above, and Q.sub.4 and Q.sub.5 may optionally be linked (e.g., coupled) to each other to form a saturated or unsaturated ring.

[0091] For example, Q.sub.4 and Q.sub.5 may combine (e.g., couple) with the nitrogen atom to form a carbazole ring.

[0092] For example, Ar.sub.11 to Ar.sub.16 and Ar.sub.21 to Ar.sub.29 may each independently be selected from the group consisting of:

[0093] a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0094] a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and

[0095] a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, a dibenzosilolyl group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), and --N(Q.sub.44)(Q.sub.45), and

[0096] Ar.sub.31 to Ar.sub.35 may each independently be selected from the group consisting of:

[0097] a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0098] a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and

[0099] a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), and --N(Q.sub.44)(Q.sub.45),

[0100] wherein Q.sub.1 to Q.sub.5 and Q.sub.41 to Q.sub.45 may each independently be selected from the group consisting of:

[0101] a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group;

[0102] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group; and

[0103] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

[0104] In one or more embodiments, Ar.sub.11 to Ar.sub.16 and Ar.sub.21 to Ar.sub.29 may each independently be selected from the group consisting of:

[0105] a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0106] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a naphthyridinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and

[0107] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a naphthyridinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group and a naphthyl group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), and --N(Q.sub.44)(Q.sub.45), and

[0108] Ar.sub.31 to Ar.sub.35 may each independently be selected from the group consisting of:

[0109] a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0110] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and

[0111] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group and a naphthyl group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), and --N(Q.sub.44)(Q.sub.45),

[0112] wherein Q.sub.1 to Q.sub.5 and Q.sub.41 to Q.sub.45 may each independently be selected from the group consisting of:

[0113] a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group;

[0114] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group; and

[0115] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

[0116] In one or more embodiments, Ar.sub.11 to Ar.sub.16 and Ar.sub.21 to Ar.sub.29 in Formulae 1-1, 1-2, 2, 3-1, and 3-2 may each independently be selected from the group consisting of:

[0117] a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group;

[0118] --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and

[0119] groups represented by Formulae 5-1 to 5-49 and 7-1 to 7-10, and

[0120] Ar.sub.31 to Ar.sub.35 may each independently be selected from the group consisting of:

[0121] a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group;

[0122] --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and

[0123] groups represented by Formulae 7-1 to 7-10:

##STR00008## ##STR00009## ##STR00010## ##STR00011## ##STR00012##

[0124] In Formulae 5-1 to 5-29, Z.sub.41 to Z.sub.43 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), --N(Q.sub.44)(Q.sub.45),

[0125] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, and

[0126] f1 may be an integer selected from 1 to 4, f2 may be an integer selected from 1 to 3, f3 may be an integer selected from 1 or 2, f4 may be an integer selected from 1 to 6, and f5 may be an integer selected from 1 to 5.

[0127] In Formulae 7-1 to 7-10,

[0128] Y.sub.31 and Y.sub.32 may each independently be selected from a single bond, O, S, C(Z.sub.34)(Z.sub.35), N(Z.sub.36), and Si(Z.sub.37)(Z.sub.38), provided that Y.sub.31 and Y.sub.32 are not both single bonds,

[0129] Z.sub.31 to Z.sub.38 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), --N(Q.sub.44)(Q.sub.45);

[0130] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, and a dibenzothiophenyl group,

[0131] e1 may be an integer selected from 1 to 5, e2 may be an integer selected from 1 to 7, e3 may be an integer selected from 1 to 3, e4 may be an integer selected from 1 to 4, and * and *' may each indicate a binding site to a neighboring atom,

[0132] wherein Q.sub.1 to Q.sub.5 and Q.sub.41 to Q.sub.45 may each independently be selected from the group consisting of:

[0133] a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group;

[0134] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a carbazolyl group; and

[0135] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and a carbazolyl group, each substituted with at least one selected from a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

[0136] c1 to c5 in Formulae 3-1A and 3-2A may each independently be an integer selected from 1 to 3. c1 indicates the number of Ar.sub.31 groups, and when c1 is 2 or more, the 2 or more Ar.sub.31 groups may be identical to or different from each other. c2 to c5 may each be the same as described herein in connection with c1 and Formulae 3-1A and 3-2A.

[0137] R.sub.11 to R.sub.13, R.sub.21 to R.sub.24, and R.sub.31 to R.sub.34 in Formulae 1-1, 1-2, 2, 3-1, and 3-2 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, --Si(Q.sub.11)(Q.sub.12)(Q.sub.13), --N(Q.sub.14)(Q.sub.15), and --B(Q.sub.16)(Q.sub.17), wherein Q.sub.11 to Q.sub.17 may each be the same as described above.

[0138] For example, in Formulae 1-1, 1-2, 2, 3-1, and 3-2,

[0139] R.sub.11 to R.sub.13 and R.sub.21 to R.sub.24 may each independently be selected from the group consisting of:

[0140] hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0141] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, an indolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group;

[0142] a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, an indolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, and a dibenzocarbazolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group; and

[0143] --Si(Q.sub.11)(Q.sub.12)(Q.sub.13) and --N(Q.sub.14)(Q.sub.15), and

[0144] R.sub.31 to R.sub.34 may each independently be selected from the group consisting of:

[0145] hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0146] a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group; and

[0147] a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group,

[0148] wherein Q.sub.11 to Q.sub.15 may each independently be selected from a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

[0149] In one or more embodiments, in Formulae 1-1, 1-2, 2, 3-1, and 3-2,

[0150] R.sub.11 to R.sub.13 and R.sub.21 to R.sub.24 may each independently be selected from the group consisting of:

[0151] hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0152] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group;

[0153] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, and a dibenzocarbazolyl group, each substituted with at least one selected from deuterium, C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group; and

[0154] --Si(Q.sub.11)(Q.sub.12)(Q.sub.13) and --N(Q.sub.14)(Q.sub.15), and

[0155] R.sub.31 to R.sub.34 may each independently be selected from the group consisting of:

[0156] hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0157] a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group; and

[0158] a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group,

[0159] wherein Q.sub.11 to Q.sub.15 may each independently be selected from a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

[0160] b11 to b13, b21 to b24, and b31 to b34 in Formulae 1-1, 1-2, 2, 3-1, and 3-2 may each independently be an integer selected from 0 to 8. b11 indicates the number of R.sub.11 groups, and when b11 is 2 or more, the 2 or more R.sub.11 groups may be identical to or different from each other. b12, b13, b21 to b24, and b31 to b34 may each be the same as described herein in connection with b11 and Formulae 1-1, 1-2, 2, 3-1, and 3-2.

[0161] For example, b11 to b13, b21 to b24, and b31 to b34 in Formulae 1-1, 1-2, 2, 3-1, and 3-2 may each independently be an integer selected from 0 to 6.

[0162] In one or more embodiments, the first compound may be represented by one selected from Formulae 1-11 to 1-15 and 1-21 to 1-23, but embodiments of the present disclosure are not limited thereto:

##STR00013## ##STR00014##

[0163] In Formulae 1-11 to 1-15 and 1-21 to 1-23,

[0164] A.sub.11, A.sub.13, X.sub.11, X.sub.12, R.sub.11 to R.sub.13, and b11 to b13 may each be the same as described above.

[0165] For example, A.sub.11 and A.sub.13 in Formulae 1-11 to 1-15 and 1-21 to 1-23 may each independently be selected from a benzene, a naphthalene, an anthracene, and a pyridine.

[0166] For example, b12 in Formulae 1-11 to 1-13, 1-21, and 1-22 may be an integer selected from 0 to 2, and b12 in Formulae 1-14, 1-15, and 1-23 may be an integer selected from 0 to 4.

[0167] In one or more embodiments, the second compound may be represented by Formula 2-1, but embodiments of the present disclosure are not limited thereto:

##STR00015##

[0168] In Formula 2-1,

[0169] A.sub.21, A.sub.24, X.sub.21, L.sub.21, L.sub.26, a21, a26, Ar.sub.21, R.sub.21 to R.sub.24, b21, and b24 may each be the same as described above, and b22 and b23 may each be an integer selected from 0 to 3.

[0170] In one or more embodiments, the second compound may be represented by one selected from Formulae 2-11 to 2-15:

##STR00016## ##STR00017##

[0171] In Formulae 2-11 to 2-15, X.sub.21, L.sub.21, L.sub.26, a21, a26, Ar.sub.21, R.sub.21 to R.sub.24 and b21, and b24 may each be the same as described above, and

[0172] b22 and b23 may each independently be an integer selected from 0 to 3.

[0173] In Formulae 2-11 to 2-15,

[0174] A.sub.21 and A.sub.24 may each independently be selected from a benzene, a naphthalene, a pyridine, a cinnoline, and a naphthyridine.

[0175] In one or more embodiments, the third compound may be represented by one selected from Formulae 3A to 3C:

##STR00018##

[0176] In Formulae 3A to 3C,

[0177] A.sub.31 to A.sub.34, L.sub.31, L.sub.32, L.sub.35, a31, a32, a35, Ar.sub.31 to Ar.sub.35, c1, c2, c5, R.sub.31 to R.sub.34, b31 to b34, Q.sub.4, and Q.sub.5 may each be the same as described above.

[0178] In one or more embodiments, the third compound may be represented by one selected from Formulae 3A(1), 3A(2), 3B(1) to 3B(3), and 3C(1):

##STR00019## ##STR00020##

[0179] In Formulae 3A(1), 3A(2), 3B(1) to 3B(3), and 3C(1),

[0180] L.sub.35, a31, a35, Ar.sub.31 to Ar.sub.35, c1, c5, R.sub.31 to R.sub.34, Q.sub.4, and Q.sub.5 may each be the same as described above,

[0181] b31 and b33 may each independently be an integer selected from 0 to 4; b32 and b34 may each independently be an integer selected from 0 to 3,

[0182] Z.sub.1 may be selected from hydrogen and --N(Q.sub.44)(Q.sub.45), Q.sub.44, and Q.sub.45 may each be the same as described above,

[0183] d1 may be an integer selected from 0 to 4,

[0184] Z.sub.31 to Z.sub.34 may each independently be selected from the group consisting of:

[0185] hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.10 alkyl group, and a C.sub.1-C.sub.10 alkoxy group; and

[0186] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and a carbazolyl group, and

[0187] e4 may be an integer selected from 0 to 4.

[0188] In one or more embodiments, the first compound may be selected from Compounds 100 to 272 and 301 to 374,

[0189] the second compound may be selected from Compounds 101A to 212A and 101B to 230B, and

[0190] the third compound may be selected from Compounds A1 to A27, B1 to B25, C1 to C16, D1 to D9, E1 to E10, and F1 to F32, but embodiments of the present disclosure are not limited thereto:

##STR00021## ##STR00022## ##STR00023## ##STR00024## ##STR00025## ##STR00026## ##STR00027## ##STR00028## ##STR00029## ##STR00030## ##STR00031## ##STR00032## ##STR00033## ##STR00034## ##STR00035## ##STR00036## ##STR00037## ##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044## ##STR00045## ##STR00046## ##STR00047## ##STR00048##

##STR00049## ##STR00050## ##STR00051## ##STR00052## ##STR00053## ##STR00054## ##STR00055## ##STR00056## ##STR00057## ##STR00058## ##STR00059## ##STR00060## ##STR00061## ##STR00062## ##STR00063## ##STR00064## ##STR00065## ##STR00066## ##STR00067## ##STR00068## ##STR00069##

##STR00070## ##STR00071## ##STR00072## ##STR00073## ##STR00074## ##STR00075## ##STR00076## ##STR00077## ##STR00078## ##STR00079## ##STR00080## ##STR00081## ##STR00082## ##STR00083## ##STR00084## ##STR00085## ##STR00086## ##STR00087## ##STR00088## ##STR00089## ##STR00090##

##STR00091## ##STR00092## ##STR00093## ##STR00094## ##STR00095## ##STR00096## ##STR00097## ##STR00098## ##STR00099## ##STR00100## ##STR00101## ##STR00102##

##STR00103## ##STR00104## ##STR00105## ##STR00106## ##STR00107## ##STR00108## ##STR00109## ##STR00110## ##STR00111## ##STR00112##

##STR00113## ##STR00114## ##STR00115## ##STR00116## ##STR00117## ##STR00118## ##STR00119## ##STR00120## ##STR00121## ##STR00122## ##STR00123## ##STR00124## ##STR00125##

##STR00126## ##STR00127## ##STR00128## ##STR00129## ##STR00130## ##STR00131## ##STR00132## ##STR00133## ##STR00134##

[0191] When at least one selected from the first compound (represented by one selected from Formulae 1-1 and 1-2) and the second compound (represented by Formula 2) is used in an organic light-emitting device (for example, as a material for forming an emission layer, such as a host in a phosphorescent emission layer), excitons may be efficiently or suitably formed in the emission layer, thus leading to high efficiency characteristics. When the emission layer includes the first compound and the second compound, the charge balance between holes and electrons may be significantly improved, and high efficiency and a long lifespan may be obtained. However, if a suitable material is not used to form a hole transport region (for example, an emission auxiliary layer), electrons may leak from the emission layer to the hole transport region (for example, to a hole transport layer). Accordingly, a higher driving voltage may be required and the efficiency of an organic light-emitting device may be substantially decreased. Accordingly, when the third compound represented by one selected from Formulae 3-1A and 3-2A is used as a material for forming a hole transport region (for example, an emission auxiliary layer), electrons leaking from the emission layer to the hole transport region (for example, to a hole transport layer) may be minimized or reduced, and accordingly, most of the excitons formed in the emission layer may be able to contribute to emission, leading to high efficiency. Also, deterioration of the material due to current leakage may be reduced, such that a smaller current is needed to obtain the same luminance, thereby enabling a long lifespan.

[0192] For example, the emission layer may include at least one compound selected from the first compound and the second compound, and

[0193] the first compound may be selected from Compounds 100 to 272, and the second compound may be selected from Compounds 101B to 230B; or

[0194] the first compound may be selected from Compounds 301 to 374, and the second compound may be selected from Compounds 101A to 212A.

[0195] The organic layer 150 may further include a hole transport region between the first electrode and the emission layer. The organic layer 150 may further include an electron transport region between the emission layer and the second electrode.

[0196] The hole transport region may have a single-layered structure or a multi-layered structure including 2 or more layers. In one or more embodiments, the hole transport region may include a single material or 2 or more different materials.

[0197] The hole transport region may include at least one selected from a hole injection layer (HIL), a hole transport layer (HTL), a buffer layer, an electron blocking layer (EBL), and an emission auxiliary layer, and the electron transport region may include at least one selected from a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL), but embodiments of the structure of the hole transport region are not limited thereto.

[0198] The hole transport region may have a structure of hole injection layer/hole transport layer, a structure of hole injection layer/hole transport layer/emission auxiliary layer, a structure of hole injection layer/hole transport layer/buffer layer/emission auxiliary layer, a structure of hole injection layer/emission auxiliary layer, a structure of hole injection layer/buffer layer/emission auxiliary layer, a structure of hole transport layer/emission auxiliary layer, or a structure of hole transport layer/buffer layer/emission auxiliary layer, wherein the layers constituting each of these structures are sequentially stacked on the first electrode 110 in each stated order, but embodiments of the structure of the hole transport region are not limited thereto.

[0199] When the hole transport region includes a hole injection layer, the hole injection layer may be formed on the first electrode 110 using one or more suitable methods selected from vacuum deposition, spin coating, casting, a Langmuir-Blodgett (LB) method, ink-jet printing, laser-printing, and laser-induced thermal imaging. The hole transport layer, the emission auxiliary layer, and the buffer layer may each be formed in the same manner used to form the hole injection layer.

[0200] When the hole injection layer is formed by vacuum deposition, for example, the vacuum deposition may be performed at a deposition temperature of about 100 to about 500.degree. C., at a vacuum degree of about 10.sup.-8 to about 10.sup.-3 torr, and at a deposition rate of about 0.01 to about 100 .ANG./sec, depending on the compound to be deposited in the hole injection layer, and the structure of the hole injection layer to be formed.

[0201] When the hole injection layer is formed by spin coating, the spin coating may be performed at a coating rate of about 2,000 rpm to about 5,000 rpm and at a temperature of about 80.degree. C. to 200.degree. C., depending on the compound to be deposited in the hole injection layer, and the structure of the hole injection layer to be formed.

[0202] The hole transport layer, the emission auxiliary layer, and the buffer layer may each be formed in the same manner used to form the hole injection layer.

[0203] For example, the hole transport region may include the third compound.

[0204] For example, the hole transport region may include the emission auxiliary layer, and the emission auxiliary layer may include the third compound.

[0205] The hole transport region may further include, in addition to the third compound, at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB, .beta.-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, DNTPD, TCTA (4,4',4''-tris(N-carbazolyl)triphenylamine), PANI/DBSA (polyaniline/dodecylbenzenesulfonic acid), PEDOT/PSS (poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate)), PANI/CSA (polyaniline/camphor sulfonic acid), PANI/PSS (polyaniline/poly(4-styrenesulfonate)), and compounds represented by Formulae 201 and 202:

##STR00135## ##STR00136## ##STR00137## ##STR00138##

[0206] In Formula 201 and 202,

[0207] L.sub.201 to L.sub.205 may each be the same as described herein in connection with L.sub.11;

[0208] xa1 to xa4 may each independently be selected from 0, 1, 2, and 3;

[0209] xa5 may be selected from 1, 2, 3, 4, and 5; and

[0210] R.sub.201 to R.sub.204 may each independently be selected from a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

[0211] For example, in Formulae 201 and 202,

[0212] L.sub.201 to L.sub.205 may each independently be selected from the group consisting of:

[0213] a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorene group, a dibenzofluorene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, a triazinylene group; and

[0214] a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group;

[0215] xa1 to xa4 may each independently be selected from 0, 1, and 2;

[0216] xa5 may be selected from 1, 2, and 3; and

[0217] R.sub.201 to R.sub.204 may each independently be selected from the group consisting of:

[0218] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group; and

[0219] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an azulenyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, but embodiments of the present disclosure are not limited thereto.

[0220] The compound represented by Formula 201 may be represented by Formula 201A:

##STR00139##

[0221] In some embodiments, the compound represented by Formula 201 may be represented by Formula 201A-1, but embodiments of the present disclosure are not limited thereto:

##STR00140##

[0222] In some embodiments, the compound represented by Formula 202 may be represented by Formula 202A, but embodiments of the present disclosure are not limited thereto:

##STR00141##

[0223] In Formulae 201A, 201A-1, and 202A, L.sub.201 to L.sub.203, xa1 to xa3, xa5, and R.sub.202 to R.sub.204 may each be the same as described above, R.sub.211 and R.sub.212 may each be the same as described herein in connection with R.sub.203, and R.sub.213 to R.sub.216 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60aryloxy group, a C.sub.6-C.sub.60arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group.

[0224] For example, in Formulae 201A, 201A-1, and 202A,

[0225] L.sub.201 to L.sub.203 may each independently be selected from the group consisting of:

[0226] a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, a triazinylene group; and

[0227] a phenylene group, a naphthylene group, a fluorenylene group, a spiro-fluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenanthrenylene group, an anthracenylene group, a pyrenylene group, a chrysenylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, a quinolinylene group, an isoquinolinylene group, a quinoxalinylene group, a quinazolinylene group, a carbazolylene group, and a triazinylene group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group;

[0228] xa1 to xa3 may each independently be selected from 0 and 1;

[0229] R.sub.203, R.sub.204, R.sub.211, and R.sub.212 may each independently be selected from the group consisting of:

[0230] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group; and

[0231] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group and a triazinyl group;

[0232] R.sub.213 and R.sub.214 may each independently be selected from the group consisting of:

[0233] a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0234] a C.sub.1-C.sub.20 alkyl group and a C.sub.1-C.sub.20 alkoxy group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group;

[0235] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group; and

[0236] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group;

[0237] R.sub.215 and R.sub.216 may each independently be selected from the group consisting of:

[0238] hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group;

[0239] a C.sub.1-C.sub.20 alkyl group and a C.sub.1-C.sub.20 alkoxy group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group;

[0240] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a triazinyl group; and

[0241] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group; and

[0242] xa5 may be selected from 1 and 2.

[0243] R.sub.213 and R.sub.214 in Formulae 201A and 201A-1 may be linked (e.g., coupled) to each other to form a saturated or unsaturated ring.

[0244] The compound represented by Formula 201 and the compound represented by Formula 202 may include Compounds HT1 to HT20, but embodiments of the present disclosure are not limited thereto:

##STR00142## ##STR00143## ##STR00144## ##STR00145## ##STR00146## ##STR00147##

[0245] The thickness of the hole transport region may be about 100 .ANG. to about 10,000 .ANG., and in some embodiments, about 100 .ANG. to about 1,000 .ANG.. When the hole transport region includes a hole injection layer and a hole transport layer, the thickness of the hole injection layer may be about 100 .ANG. to about 10,000 .ANG., and in some embodiments, about 100 .ANG. to about 1,000 .ANG.. The thickness of the hole transport layer may be about 50 .ANG. to about 2,000 .ANG., and in some embodiments, about 100 .ANG. to about 1,500 .ANG.. When the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

[0246] When the hole transport region includes an emission auxiliary layer, the thickness of the emission auxiliary layer may be about 10 .ANG. to about 2,000 .ANG., and in some embodiments, about 50 .ANG. to about 1,000 .ANG.. When the thickness of the emission auxiliary layer is within these ranges, the hole transport layer may have satisfactory hole transporting ability without a substantial increase in driving voltage.

[0247] The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

[0248] The p-dopant may be one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto. Non-limiting examples of the p-dopant may include a quinone derivative (such as tetracyanoquinonedimethane (TCNQ)) a metal oxide (such as a tungsten oxide and/or a molybdenum oxide), Compound HT-D1, and Compound HT-D2, but embodiments of the present disclosure are not limited thereto.

##STR00148##

[0249] The hole transport region may further include, in addition to the hole injection layer and the hole transport layer, at least one selected from a buffer layer, an emission auxiliary layer, and an electron blocking layer. Since the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer (e.g., be used to adjust the optical resonance distance to match the wavelength of light emitted from the emission layer), the light-emission efficiency of a formed organic light-emitting device may be improved. Materials that are included in the hole transport region may also be included in the buffer layer. The electron blocking layer may prevent or reduce injection of electrons from the electron transport region.

[0250] When the hole transport region includes the emission auxiliary layer, the emission auxiliary layer may directly contact the emission layer, but embodiments of the present disclosure are not limited thereto.

[0251] An emission layer may be formed on the first electrode 110 or on the hole transport region using one or more suitable methods selected from vacuum deposition, spin coating, casting, a LB method, ink-jet printing, laser-printing, and laser-induced thermal imaging. When the emission layer is formed by vacuum deposition and/or spin coating, the deposition and coating conditions used for the emission layer may be similar to the deposition and coating conditions used for the hole injection layer.

[0252] When the organic light-emitting device 10 is a full color organic light-emitting device, the emission layer 150 may be patterned into a red emission layer, a green emission layer, or a blue emission layer, according to a sub pixel. In some embodiments, the emission layer 150 may have a stacked structure including a red emission layer, a green emission layer, and a blue emission layer, or may include a red-light emission material, a green-light emission material, and a blue-light emission material, which may be mixed with each other in a single layer to thereby emit white light.

[0253] The emission layer may include a host and a dopant.

[0254] The emission layer may include at least one compound selected from the first compound and the second compound.

[0255] The first compound and the second compound may each act as a host in the emission layer.

[0256] For example, the emission layer may include the first compound, and the emission auxiliary layer may include the third compound; or

[0257] the emission layer may include the second compound, and the emission auxiliary layer may include the third compound.

[0258] In one or more embodiments, the emission layer may include the first compound and the second compound, and the emission auxiliary layer may include the third compound;

[0259] the emission layer may include a first host selected from the first compound and a second host selected from the second compound, and the emission auxiliary layer may include the third compound;

[0260] the emission layer may include a third host and a fourth host, each selected from the first compound, the third host and the fourth host are different from each other, and the emission auxiliary layer may include the third compound; or

[0261] the emission layer may include a fifth host and a sixth host, each selected from the second compound, the fifth host and the sixth host are different from each other, and the emission auxiliary layer may include the third compound, but embodiments of the present disclosure are not limited thereto.

[0262] The emission layer may include, in addition to at least one compound selected from the first compound and the second compound, at least one selected from TPBi, TBADN, ADN, CBP, CDBP, and TCP:

##STR00149## ##STR00150##

[0263] The dopant may further include at least one selected from a fluorescent dopant and a phosphorescent dopant.

[0264] The phosphorescent dopant may include an organometallic complex represented by Formula 401:

##STR00151##

[0265] In Formula 401,

[0266] M may be selected from iridium (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm);

[0267] X.sub.401 to X.sub.404 may each independently be selected from nitrogen and carbon;

[0268] rings A.sub.401 and A.sub.402 may each independently be selected from a substituted or unsubstituted benzene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted fluorene, a substituted or unsubstituted spiro-fluorene, a substituted or unsubstituted indene, a substituted or unsubstituted pyrrole, a substituted or unsubstituted thiophene, a substituted or unsubstituted furan, a substituted or unsubstituted imidazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted thiazole, a substituted or unsubstituted isothiazole, a substituted or unsubstituted oxazole, a substituted or unsubstituted isoxazole, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted quinoline, a substituted or unsubstituted isoquinoline, a substituted or unsubstituted benzoquinoline, a substituted or unsubstituted quinoxaline, a substituted or unsubstituted quinazoline, a substituted or unsubstituted carbazole, a substituted or unsubstituted benzimidazole, a substituted or unsubstituted benzofuran, a substituted or unsubstituted benzothiophene, a substituted or unsubstituted isobenzothiophene, a substituted or unsubstituted benzoxazole, a substituted or unsubstituted isobenzoxazole, a substituted or unsubstituted triazole, a substituted or unsubstituted oxadiazole, a substituted or unsubstituted triazine, a substituted or unsubstituted dibenzofuran, and a substituted or unsubstituted dibenzothiophene;

[0269] at least one substituent of the substituted benzene, substituted naphthalene, substituted fluorene, substituted spiro-fluorene, substituted indene, substituted pyrrole, substituted thiophene, substituted furan, substituted imidazole, substituted pyrazole, substituted thiazole, substituted isothiazole, substituted oxazole, substituted isoxazole, substituted pyridine, substituted pyrazine, substituted pyrimidine, substituted pyridazine, substituted quinoline, substituted isoquinoline, substituted benzoquinoline, substituted quinoxaline, substituted quinazoline, substituted carbazole, substituted benzimidazole, substituted benzofuran, substituted benzothiophene, substituted isobenzothiophene, substituted benzoxazole, substituted isobenzoxazole, substituted triazole, substituted oxadiazole, substituted triazine, substituted dibenzofuran, and substituted dibenzothiophene may be selected from the group consisting of:

[0270] deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group;

[0271] a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, and a C.sub.1-C.sub.60 alkoxy group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --N(Q.sub.401)(Q.sub.402), --Si(Q.sub.403)(Q.sub.404)(Q.sub.405), and --B(Q.sub.406)(Q.sub.407),

[0272] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10heterocycloalkyl, C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group;

[0273] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10heterocycloalkyl, C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, --N(Q.sub.411)(Q.sub.412), --Si(Q.sub.413)(Q.sub.414)(Q.sub.415), and --B(Q.sub.416)(Q.sub.417),

[0274] --N(Q.sub.421)(Q.sub.422), --Si(Q.sub.423)(Q.sub.424)(Q.sub.425), and --B(Q.sub.426)(Q.sub.427),

[0275] L.sub.401 may be an organic ligand;

[0276] xc1 may be selected from 1, 2, and 3;

[0277] xc2 may be selected from 0, 1, 2, and 3,

[0278] wherein Q.sub.401 to Q.sub.407, Q.sub.411 to Q.sub.417, and Q.sub.421 to Q.sub.427 may each independently be selected from hydrogen, C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.6-C.sub.60 aryl group, and a C.sub.1-C.sub.60 heteroaryl group; and

[0279] L.sub.401 may be a monovalent, divalent, or trivalent organic ligand. For example, L.sub.401 may be selected from a halogen ligand (for example, Cl and/or F), a diketone ligand (for example, acetylacetonate, 1,3-diphenyl-1,3-propandionate, 2,2,6,6-tetramethyl-3,5-heptandionate, and/or hexafluoroacetonate), a carboxylic acid ligand (for example, picolinate, dimethyl-3-pyrazolecarboxylate, and/or benzoate), a carbon monoxide ligand, an isonitrile ligand, a cyano ligand, and a phosphorous ligand (for example, phosphine and/or phosphite), but embodiments of the present disclosure are not limited thereto.

[0280] When A.sub.401 in Formula 401 has two or more substituents, the substituents of A.sub.401 may be linked (e.g., coupled) to each other to form a saturated or unsaturated ring.

[0281] When A.sub.402 in Formula 401 has two or more substituents, the substituents of A.sub.402 may be linked (e.g., coupled) to each other to form a saturated or unsaturated ring.

[0282] When xc1 in Formula 401 is 2 or more, a plurality of ligands

##STR00152##

in Formula 401 may be identical to or different from each other. When xc1 in Formula 401 is 2 or more, A.sub.401 and A.sub.402 may be connected to A.sub.401 and A.sub.402, respectively, of other neighboring ligands with or without a linker (for example, a C.sub.1-C.sub.5 alkylene group, a C.sub.2-C.sub.5 alkenylene group, --N(R')-- (wherein R' is a C.sub.1-C.sub.10 alkyl group or a C.sub.6-C.sub.20 aryl group) and/or --C(.dbd.O)--) therebetween.

[0283] The phosphorescent dopant may include at least one selected from Compounds PD1 to PD76, but embodiments of the present disclosure are not limited thereto:

##STR00153## ##STR00154## ##STR00155## ##STR00156## ##STR00157## ##STR00158## ##STR00159## ##STR00160## ##STR00161## ##STR00162## ##STR00163## ##STR00164## ##STR00165## ##STR00166## ##STR00167##

[0284] In one or more embodiments, the phosphorescent dopant may include PtOEP:

##STR00168##

[0285] In one or more embodiments, the fluorescent dopant may include a compound represented by Formula 501:

##STR00169##

[0286] In Formula 501,

[0287] Ar.sub.501 may be selected from a naphthalene, a heptalene, a fluorenene, a spiro-fluorenene, a benzofluorenene, a dibenzofluorenene, a phenalene, a phenanthrene, an anthracene, a fluoranthene, a triphenylene, a pyrene, a chrysene, a naphthacene, a picene, a perylene, a pentaphene, an indenoanthracene; and

[0288] a naphthalene, a heptalene, a fluorene, a spiro-fluorene, a benzofluorene, a dibenzofluorene, a phenalene, a phenanthrene, an anthracene, a fluoranthene, a triphenylene, a pyrene, a chrysene, naphthacene, a picene, a perylene, a pentaphene, and an indenoanthracene, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group and --Si(Q.sub.5o1)(Q.sub.502)(Q.sub.5o3) (wherein Q.sub.501 to Q.sub.503 may each be independently selected from hydrogen, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.6-C.sub.60 aryl group, and a C.sub.1-C.sub.60 heteroaryl group),

[0289] L.sub.501 to L.sub.503 may each be the same as described herein in connection with L.sub.201;

[0290] R.sub.501 and R.sub.502 may each independently be selected from the group consisting of:

[0291] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazole group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group; and

[0292] a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group and a dibenzothiophenyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group and a dibenzothiophenyl group,

[0293] xd1 to xd3 may each independently be selected from 0, 1, 2, and 3, and

[0294] xd4 may be selected from 1, 2, 3 and 4.

[0295] The fluorescent dopant may include at least one selected from Compounds FD1 to FD8:

##STR00170## ##STR00171## ##STR00172##

[0296] The amount of the dopant in the emission layer may be, in general, about 0.01 to about 15 parts by weight based on 100 parts by weight of the host, but embodiments of the present disclosure are not limited thereto.

[0297] The weight ratio of the first host to the second host, the weight ratio of the third host to the fourth host, and the weight ratio of the fifth host to the sixth host in the emission layer may each independently be 99:1 to 1:99, and in some embodiments, 80:20 to 20:80. In some embodiments, the weight ratio of the first host to the second host, the weight ratio of the third host to the fourth host, and the weight ratio of the fifth host to the sixth host in the emission layer may each independently be 50:50, but embodiments of these weight ratios are not limited thereto.

[0298] The thickness of the emission layer may be about 100 .ANG. to about 1,000 .ANG., and in some embodiments, about 200 .ANG. to about 600 .ANG.. When the thickness of the emission layer is within these ranges, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

[0299] An electron transport region may be on the emission layer.

[0300] The electron transport region may include at least one selected from a hole blocking layer, an electron transport layer (ETL), and an electron injection layer, but embodiments of the present disclosure are not limited thereto.

[0301] When the electron transport region includes a hole blocking layer, the hole blocking layer may be formed on the emission layer using one or more suitable methods selected from vacuum deposition, spin coating, casting, a Langmuir-Blodgett (LB) method, ink-jet printing, laser-printing, and/or laser-induced thermal imaging. When the hole blocking layer is formed by vacuum deposition and/or spin coating, the deposition and coating conditions used for the hole blocking layer may be similar to the deposition and coating conditions used for the hole injection layer.

[0302] The hole blocking layer may include, for example, at least one selected from BCP and Bphen, but embodiments of the present disclosure are not limited thereto.

##STR00173##

[0303] The thickness of the hole blocking layer may be about 20 .ANG. to about 1,000 .ANG., and in some embodiments, about 30 .ANG. to about 300 .ANG.. When the thickness of the hole blocking layer is within these ranges, the hole blocking layer may have improved hole blocking ability without a substantial increase in driving voltage.

[0304] The electron transport region may include an electron transport layer. The electron transport layer may be formed on the emission layer or on the hole blocking layer using one or more suitable methods selected from vacuum deposition, spin coating, casting, a LB method, ink-jet printing, laser-printing, and laser-induced thermal imaging. When an electron transport layer is formed by vacuum deposition and/or spin coating, the deposition and coating conditions used for the electron transport layer may be similar to the deposition and coating conditions used for the hole injection layer.

[0305] The electron transport layer may further include at least one selected from BCP, Bphen, Alq.sub.3, Balq, TAZ, and NTAZ:

##STR00174##

[0306] In one or more embodiments, the electron transport layer may further include at least one selected from compounds represented by Formula 601:

Ar.sub.601-[(L.sub.601).sub.xe1-E.sub.601].sub.xe2. Formula 601

[0307] In Formula 601,

[0308] Ar.sub.6o1 may be the same as described herein in connection with Ar.sub.301;

[0309] L.sub.601 may be the same as described herein in connection with L.sub.201;

[0310] E.sub.601 may be selected from the group consisting of:

[0311] a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group; and

[0312] a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, and a dibenzocarbazolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, and a dibenzocarbazolyl group;

[0313] xe1 may be selected from 0, 1, 2, and 3; and

[0314] xe2 may be selected from 1, 2, 3, and 4.

[0315] In one or more embodiments, the electron transport layer may include at least one compound represented by Formula 602:

##STR00175##

[0316] In Formula 602,

[0317] X.sub.611 may be selected from N and C-(L.sub.611).sub.xe611-R.sub.611, X.sub.612 may be selected from N and C-(L.sub.612).sub.xe612-R.sub.612, X.sub.613 may be selected from N and C-(L.sub.613).sub.xe613-R.sub.613, and at least one selected from X.sub.611 to X.sub.613 may be N;

[0318] L.sub.611 to L.sub.616 may each be the same as described herein in connection with L.sub.201;

[0319] R.sub.611 to R.sub.616 may each independently be selected from the group consisting of:

[0320] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group; and

[0321] a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, and a triazinyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an azulenyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group and a triazinyl group; and

[0322] xe611 to xe616 may each independently be selected from 0, 1, 2, and 3.

[0323] The compound represented by Formula 601 and the compound represented by Formula 602 may each include at least one selected from Compounds ET1 to ET15:

##STR00176## ##STR00177## ##STR00178## ##STR00179## ##STR00180##

[0324] The thickness of the electron transport layer may be about 100 .ANG. to about 1,000 .ANG., and in some embodiments, about 150 .ANG. to about 500 .ANG.. When the thickness of the electron transport layer is within these ranges described above, the electron transport layer may have satisfactory electron transport characteristics without a substantial increase in driving voltage.

[0325] Also, the electron transport layer may further include, in addition to the materials described above, a metal-containing material.

[0326] The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) and/or ET-D2:

##STR00181##

[0327] The electron transport region may include an electron injection layer that facilitates injection of electrons from the second electrode 190.

[0328] The electron injection layer may be formed on the electron transport layer using one or more suitable methods selected from vacuum deposition, spin coating, casting, a LB method, ink-jet printing, laser-printing, and laser-induced thermal imaging. When an electron injection layer is formed by vacuum deposition and/or spin coating, the deposition and coating conditions used for the electron injection layer may be similar to the deposition and coating conditions used for the hole injection layer.

[0329] The electron injection layer may include at least one selected from LiF, NaCl, CsF, Li.sub.2O, BaO, and LiQ.

[0330] The thickness of the electron injection layer may be about 1 .ANG. to about 100 .ANG., and in some embodiments, about 3 .ANG. to about 90 .ANG.. When the thickness of the electron injection layer is within these ranges, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

[0331] The second electrode 190 may be on the organic layer 150. The second electrode 190 may be a cathode that is an electron injection electrode, and in this regard, the material for forming the second electrode 190 may be a material having a low work function. Non-limiting examples of such material may include a metal, an alloy, an electrically conductive compound, and a mixture thereof. Non-limiting examples of the second electrode 190 may include lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al--Li), calcium (Ca), magnesium-indium (Mg--In), and magnesium-silver (Mg--Ag). In some embodiments, the material for forming the second electrode 190 may be ITO and/or IZO. The second electrode 190 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode.

[0332] Hereinbefore, the organic light-emitting device has been described with reference to the drawing, but embodiments of the present disclosure are not limited thereto.

[0333] The term "C.sub.1-C.sub.60 alkyl group" as used herein refers to a linear or branched aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and non-limiting examples thereof may include a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group. The term "C.sub.1-C.sub.60 alkylene group" as used herein refers to a divalent group having substantially the same structure as the C.sub.1-C.sub.60 alkyl group.

[0334] The term "C.sub.1-C.sub.60 alkoxy group" as used herein refers to a monovalent group represented by --O-A.sub.101 (wherein A.sub.101 is the C.sub.1-C.sub.60 alkyl group), and non-limiting examples thereof may include a methoxy group, an ethoxy group, and an isopropyloxy group.

[0335] The term "C.sub.2-C.sub.60 alkenyl group" as used herein refers to a hydrocarbon group having at least one carbon-carbon double bond in the body (e.g., middle) or at the terminus of the C.sub.2-C.sub.60 alkyl group, and non-limiting examples thereof may include an ethenyl group, a propenyl group, and a butenyl group. The term "C.sub.2-C.sub.60 alkenylene group" as used herein refers to a divalent group having substantially the same structure as the C.sub.2-C.sub.60 alkenyl group.

[0336] The term "C.sub.2-C.sub.60 alkynyl group" as used herein refers to a hydrocarbon group having at least one carbon-carbon triple bond in the body (e.g., middle) or at the terminus of the C.sub.2-C.sub.60 alkyl group, and non-limiting examples thereof may include an ethynyl group and a propynyl group. The term "C.sub.2-C.sub.60 alkynylene group" as used herein refers to a divalent group having substantially the same structure as the C.sub.2-C.sub.60 alkynyl group.

[0337] The term "C.sub.3-C.sub.10 cycloalkyl group" as used herein refers to a monovalent hydrocarbon monocyclic group having 3 to 10 carbon atoms, and non-limiting examples thereof may include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term "C.sub.3-C.sub.10 cycloalkylene group" as used herein refers to a divalent group having substantially the same structure as the C.sub.3-C.sub.10 cycloalkyl group.

[0338] The term "C.sub.1-C.sub.10 heterocycloalkyl group" as used herein refers to a monovalent monocyclic group having at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom in addition to 1 to 10 carbon atoms, and non-limiting examples thereof may include a tetrahydrofuranyl group and a tetrahydrothiophenyl group. The term "C.sub.1-C.sub.10 heterocycloalkylene group" as used herein refers to a divalent group having substantially the same structure as the C.sub.1-C.sub.10 heterocycloalkyl group.

[0339] The term "C.sub.3-C.sub.10 cycloalkenyl group" as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one double bond in the ring thereof, and does not have aromaticity. Non-limiting examples thereof may include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term "C.sub.3-C.sub.10 cycloalkenylene group" as used herein refers to a divalent group having substantially the same structure as the C.sub.3-C.sub.10 cycloalkenyl group.

[0340] The term "C.sub.1-C.sub.10 heterocycloalkenyl group" as used herein refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, silicon (Si), phosphorus (P), and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one double bond in its ring. Non-limiting examples of the C.sub.1-C.sub.10 heterocycloalkenyl group may include a 2,3-hydrofuranyl group and a 2,3-hydrothiophenyl group. The term "C.sub.1-C.sub.10 heterocycloalkenylene group" as used herein refers to a divalent group having substantially the same structure as the C.sub.1-C.sub.10 heterocycloalkenyl group.

[0341] The term "C.sub.6-C.sub.60 aryl group" as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term "C.sub.6-C.sub.60 group" as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C.sub.6-C.sub.60 aryl group may include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C.sub.6-C.sub.60 aryl group and the C.sub.6-C.sub.60 arylene group each include two or more rings, the rings may be fused (e.g., coupled) to each other.

[0342] The term "C.sub.1-C.sub.60 heteroaryl group" as used herein refers to a monovalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom in addition to 1 to 60 carbon atoms. The term "C.sub.1-C.sub.60 heteroarylene group" as used herein refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, Si, P, and S as a ring-forming atom, in addition to 1 to 60 carbon atoms. Non-limiting examples of the C.sub.1-C.sub.60 heteroaryl group may include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C.sub.1-C.sub.60 heteroaryl group and the C.sub.1-C.sub.60 heteroarylene group each include two or more rings, the rings may be fused (e.g., coupled) to each other.

[0343] The term "C.sub.6-C.sub.60 aryloxy group" as used herein indicates --O-A.sub.102 (wherein A.sub.102 is the C.sub.6-C.sub.60 aryl group), and the term "C.sub.6-C.sub.60 arylthio group" as used herein indicates --S-A.sub.103 (wherein A.sub.103 is the C.sub.6-C.sub.60 aryl group).

[0344] The term "monovalent non-aromatic condensed polycyclic group" as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) that has two or more rings condensed (e.g., coupled) to each other, only carbon atoms as ring forming atoms, and non-aromaticity in the entire molecular structure. A non-limiting example of the monovalent non-aromatic condensed polycyclic group may be a fluorenyl group. The term "divalent non-aromatic condensed polycyclic group" as used herein refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed polycyclic group.

[0345] The term "monovalent non-aromatic condensed heteropolycyclic group" as used herein refers to a monovalent group (that has two or more rings condensed (e.g., coupled) to each other, has a heteroatom selected from N, O, Si, P, and S in addition to carbon atoms for example, 1 to 60 carbon atoms) as ring forming atoms, and has non-aromaticity in the entire molecular structure. A non-limiting example of the monovalent non-aromatic condensed heteropolycyclic group may be a carbazolyl group. The term "divalent non-aromatic condensed heteropolycyclic group" as used herein refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

[0346] As used herein, at least one substituent of the substituted C.sub.3-C.sub.10 cycloalkylene group, substituted C.sub.1-C.sub.10 heterocycloalkylene group, substituted C.sub.3-C.sub.10 cycloalkenylene group, substituted C.sub.1-C.sub.10 heterocycloalkenylene group, substituted C.sub.6-C.sub.60 arylene group, substituted C.sub.1-C.sub.60 heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C.sub.1-C.sub.60 alkyl group, substituted C.sub.2-C.sub.60 alkenyl group, substituted C.sub.2-C.sub.60 alkynyl group, substituted C.sub.1-C.sub.60 alkoxy group, substituted C.sub.3-C.sub.10 cycloalkyl group, substituted C.sub.1-C.sub.10 heterocycloalkyl group, substituted C.sub.3-C.sub.10 cycloalkenyl group, substituted C.sub.1-C.sub.10 heterocycloalkenyl group, substituted C.sub.6-C.sub.60 aryl group, substituted C.sub.6-C.sub.60 aryloxy group, substituted C.sub.6-C.sub.60 arylthio group, substituted C.sub.1-C.sub.60 heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from the group consisting of:

[0347] deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group;

[0348] a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, and a C.sub.1-C.sub.60 alkoxy group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --Si(Q.sub.21)(Q.sub.22)(Q.sub.23), --N(Q.sub.24)(Q.sub.25), and --B(Q.sub.26)(Q.sub.27);

[0349] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group;

[0350] a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --Si(Q.sub.31)(Q.sub.32)(Q.sub.33), --N(Q.sub.34)(Q.sub.35), and --B(Q.sub.36)(Q.sub.37),

[0351] --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), --N(Q.sub.44)(Q.sub.45), and --B(Q.sub.46)(Q.sub.47),

[0352] wherein Q.sub.1 to Q.sub.7, Q.sub.11 to Q.sub.17, Q.sub.21 to Q.sub.27, Q.sub.31 to Q.sub.37, and Q.sub.41 to Q.sub.47 may each independently be selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group; and

[0353] a C.sub.6-C.sub.60 aryl group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.1-C.sub.60 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

[0354] The term "Ph" as used herein represents a phenyl group, the term "Me" as used herein represents a methyl group, the term "Et" as used herein represents an ethyl group, and the term "ter-Bu" or "But" as used herein represents a tert-butyl group.

[0355] The term "biphenyl group" as used herein may refer to a monovalent group including two benzenes linked to each other via a single bond, and the term "terphenyl group" as used herein may refer to a monovalent group including three benzenes linked to one another via two single bonds.

[0356] Hereinafter, an organic light-emitting device according to an embodiment of the present disclosure will be described in more detail with reference to Synthesis Examples and Examples.

Example

Example 1-1

[0357] An anode having a structure of ITO/Ag/ITO (70 .ANG./1000 .ANG./70 .ANG.) deposited on a glass substrate was cut to a size of 50 millimeters (mm).times.50 mm.times.0.4 mm, sonicated in isopropyl alcohol and water for 10 minutes each, cleaned by exposure to ultraviolet rays for 10 minutes, and then exposed to ozone. The glass substrate was mounted on a vacuum-deposition device.

[0358] HT13 was deposited on the anode to form a hole injection layer having a thickness of about 700 .ANG.. Compound HT3 was deposited on the hole injection layer to form a hole transport layer having a thickness of about 800 .ANG.. Compound F1 was deposited on the hole transport layer to form an emission auxiliary layer having a thickness of about 750 .ANG.. Compound 235 (as a host) and Compound PD75 (as a dopant) were then co-deposited on the emission auxiliary layer at a weight ratio of about 100:3 to form an emission layer having a thickness of about 400 .ANG..

[0359] Compound ET1 and ET-D1 were co-deposited on the emission layer at a weight ratio of about 100:100 (e.g., 1:1) to form an electron transport layer having a thickness of 360 .ANG.. LiQ was then deposited on the electron transport layer to form an electron injection layer having a thickness of 10 .ANG.. Next, Mg and Ag were co-deposited on the electron injection layer to form a cathode having a thickness of 1,200 .ANG., thereby completing the manufacture of an organic light-emitting device.

Examples 1-2 to 1-20 and Comparative Examples 1-1 to 1-6

[0360] Additional organic light-emitting devices were manufactured in the same manner as in Example 1-1, except that the compounds shown in Table 1 were used to form each emission layer and emission auxiliary layer.

TABLE-US-00001 TABLE 1 Emission Emission auxiliary auxiliary layer layer Weight ratio Host material Thickness Dopant (host:dopant) Example 1-1 235 F1 750 .ANG. PD75 100:3 Example 1-2 241 F1 750 .ANG. PD75 100:3 Example 1-3 235 C7 750 .ANG. PD75 100:3 Example 1-4 223 C7 750 .ANG. PD75 100:3 Example 1-5 226 A6 350 .ANG. PD76 100:10 Example 1-6 101 A6 350 .ANG. PD76 100:10 Example 1-7 259 A6 350 .ANG. PD76 100:10 Example 1-8 237 A6 350 .ANG. PD76 100:10 Example 1-9 226 B1 350 .ANG. PD76 100:10 Example 1-10 101 B1 350 .ANG. PD76 100:10 Example 1-11 259 B1 350 .ANG. PD76 100:10 Example 1-12 237 B1 350 .ANG. PD76 100:10 Example 1-13 226 A2 350 .ANG. PD76 100:10 Example 1-14 101 A2 350 .ANG. PD76 100:10 Example 1-15 259 A2 350 .ANG. PD76 100:10 Example 1-16 237 A2 350 .ANG. PD76 100:10 Example 1-17 226 C11 350 .ANG. PD76 100:10 Example 1-18 101 C11 350 .ANG. PD76 100:10 Example 1-19 259 C11 350 .ANG. PD76 100:10 Example 1-20 237 C11 350 .ANG. PD76 100:10 Comparative 235 NPB 750 .ANG. PD75 100:3 Example 1-1 Comparative 241 NPB 750 .ANG. PD75 100:3 Example 1-2 Comparative 226 NPB 350 .ANG. PD76 100:10 Example 1-3 Comparative 101 NPB 350 .ANG. PD76 100:10 Example 1-4 Comparative 259 NPB 350 .ANG. PD76 100:10 Example 1-5 Comparative 237 NPB 350 .ANG. PD76 100:10 Example 1-6

Example 2-1

[0361] An anode having a structure of ITO/Ag/ITO (70 .ANG./1000 .ANG./70 .ANG.) deposited on a glass substrate was cut to a size of 50 mm.times.50 mm.times.0.4 mm, sonicated in isopropyl alcohol and water for 10 minutes each, cleaned by exposure to ultraviolet rays for 10 minutes, and then exposed to ozone. The glass substrate was mounted on a vacuum-deposition device.

[0362] HT13 was deposited on the anode to form a hole injection layer having a thickness of about 700 .ANG.. Compound HT3 was deposited on the hole injection layer to form a hole transport layer having a thickness of about 800 .ANG.. Compound F1 was deposited on the hole transport layer to form an emission auxiliary layer having a thickness of about 750 .ANG.. Compound 191A (as a host) and Compound PD75 (as a dopant) were then co-deposited on the emission auxiliary layer at a weight ratio of about 100:3 to form an emission layer having a thickness of about 400 .ANG..

[0363] Thereafter, Compound ET1 and ET-D1 were co-deposited on the emission layer at a weight ratio of about 100:100 (e.g., 1:1) to form an electron transport layer having a thickness of 360 .ANG.. LiQ was then deposited on the electron transport layer to form an electron injection layer having a thickness of 10 .ANG.. Mg and Ag were next co-deposited on the electron injection layer to form a cathode having a thickness of 1200 .ANG., thereby completing the manufacture of an organic light-emitting device.

Examples 2-2 to 2-20 and Comparative Examples 2-1 to 2-6

[0364] Organic light-emitting devices were manufactured in the same manner as in Example 2-1, except that the compounds shown in Table 2 were used to form each emission layer and emission auxiliary layer.

TABLE-US-00002 TABLE 2 Emission Emission auxiliary auxiliary layer layer Weight ratio Host material Thickness Dopant (host:dopant) Example 2-1 191A F1 750 .ANG. PD75 100:3 Example 2-2 202A F1 750 .ANG. PD75 100:3 Example 2-3 191A C7 750 .ANG. PD75 100:3 Example 2-4 202A C7 750 .ANG. PD75 100:3 Example 2-5 154A A6 350 .ANG. PD76 100:10 Example 2-6 121A A6 350 .ANG. PD76 100:10 Example 2-7 210A A6 350 .ANG. PD76 100:10 Example 2-8 156A A6 350 .ANG. PD76 100:10 Example 2-9 154A B1 350 .ANG. PD76 100:10 Example 2-10 121A B1 350 .ANG. PD76 100:10 Example 2-11 210A B1 350 .ANG. PD76 100:10 Example 2-12 156A B1 350 .ANG. PD76 100:10 Example 2-13 154A A2 350 .ANG. PD76 100:10 Example 2-14 121A A2 350 .ANG. PD76 100:10 Example 2-15 210A A2 350 .ANG. PD76 100:10 Example 2-16 156A A2 350 .ANG. PD76 100:10 Example 2-17 154A C11 350 .ANG. PD76 100:10 Example 2-18 121A C11 350 .ANG. PD76 100:10 Example 2-19 210A C11 350 .ANG. PD76 100:10 Example 2-20 156A C11 350 .ANG. PD76 100:10 Comparative 191A NPB 750 .ANG. PD75 100:3 Example 2-1 Comparative 202A NPB 750 .ANG. PD75 100:3 Example 2-2 Comparative 154A NPB 350 .ANG. PD76 100:10 Example 2-3 Comparative 121A NPB 350 .ANG. PD76 100:10 Example 2-4 Comparative 212A NPB 350 .ANG. PD76 100:10 Example 2-5 Comparative 156A NPB 350 .ANG. PD76 100:10 Example 2-6

Example 3-1

[0365] An anode having a structure of ITO/Ag/ITO (70 .ANG./1000 .ANG./70 .ANG.) deposited on a glass substrate was cut to a size of 50 mm.times.50 mm.times.0.4 mm, sonicated in isopropyl alcohol and water for 10 minutes each, cleaned by exposure to ultraviolet rays for 10 minutes, and then exposed to ozone. The glass substrate was mounted on a vacuum-deposition device.

[0366] HT13 was deposited on the anode to form a hole injection layer having a thickness of about 700 .ANG.. Compound HT3 was deposited on the hole injection layer to form a hole transport layer having a thickness of about 800 .ANG.. Compound A6 was deposited on the hole transport layer to form an emission auxiliary layer having a thickness of about 350 .ANG.. Compound 226 (as a first host), Compound 172B (as a second host), and Compound PD76 (as a dopant) were then co-deposited on the emission auxiliary layer at a weight ratio of about 50:50:10 to form an emission layer having a thickness of about 400 .ANG..

[0367] Thereafter, Compound ET1 and ET-D1 were co-deposited on the emission layer at a weight ratio of about 100:100 to form an electron transport layer having a thickness of 360 .ANG.. LiQ was then deposited on the electron transport layer to form an electron injection layer having a thickness of 10 .ANG.. Mg and Ag were next co-deposited on the electron injection layer to form a cathode having a thickness of 1200 .ANG., thereby completing the manufacture of an organic light-emitting device.

Examples 3-2 to 3-24 and Comparative Examples 3-1 to 3-6

[0368] Additional organic light-emitting devices were manufactured in the same manner as in Example 3-1, except that the compounds shown in Table 3 were used to form each emission layer and emission auxiliary layer.

TABLE-US-00003 TABLE 3 Emission Weight ratio auxiliary (First First Second layer host:Second host host material Dopant host:Dopant) Example 3-1 226 172B A6 PD76 50:50:10 Example 3-2 119 125B A6 PD76 50:50:10 Example 3-3 237 226B A6 PD76 50:50:10 Example 3-4 371 190A A6 PD76 50:50:10 Example 3-5 306 155A A6 PD76 50:50:10 Example 3-6 338 151A A6 PD76 50:50:10 Example 3-7 226 172B B1 PD76 50:50:10 Example 3-8 119 125B B1 PD76 50:50:10 Example 3-9 237 226B B1 PD76 50:50:10 Example 3-10 374 121A B1 PD76 50:50:10 Example 3-11 306 190A B1 PD76 50:50:10 Example 3-12 338 151A B1 PD76 50:50:10 Example 3-13 226 172B A2 PD76 50:50:10 Example 3-14 119 125B A2 PD76 50:50:10 Example 3-15 237 226B A2 PD76 50:50:10 Example 3-16 374 121A A2 PD76 50:50:10 Example 3-17 306 190A A2 PD76 50:50:10 Example 3-18 338 151A A2 PD76 50:50:10 Example 3-19 226 172B C11 PD76 50:50:10 Example 3-20 119 125B C11 PD76 50:50:10 Example 3-21 237 226B C11 PD76 50:50:10 Example 3-22 237 121A C11 PD76 50:50:10 Example 3-23 374 190A C11 PD76 50:50:10 Example 3-24 338 151A C11 PD76 50:50:10 Comparative 226 172B NPB PD76 50:50:10 Example 3-1 Comparative 119 125B NPB PD76 50:50:10 Example 3-2 Comparative 237 226B NPB PD76 50:50:10 Example 3-3 Comparative 374 121A NPB PD76 50:50:10 Example 3-4 Comparative 306 190A NPB PD76 50:50:10 Example 3-5 Comparative 338 151A NPB PD76 50:50:10 Example 3-6

Evaluation Example 1

[0369] The driving voltage, current density, efficiency, and lifespan of each organic light-emitting device manufactured in Examples 1-1 to 1-20, 2-1 to 2-20, and 3-1 to 3-24 and Comparative Example 1-1 to 1-6, 2-1 to 2-6, and 3-1 to 3-6 were evaluated using a Keithley 2400 SMU, a Minolta CS-1000A luminance meter, and a PR650 (Spectroscan) Source Measurement Unit (available from PhotoResearch). The T97 lifespan value indicates the time elapsed for the initial luminance (about 9000 cd/m.sup.2) to reduce by 97%. The evaluation results are shown in Tables 4 to 6.

TABLE-US-00004 TABLE 4 Driving Current First Second Third voltage density Efficiency T.sub.97 compound compound compound (V) (mA/cm.sup.2) (cd/A) (hr) Example 1-1 235 -- F1 4.1 10 38.5 489 Example 1-2 241 -- F1 4.3 10 38.1 512 Example 1-3 235 -- C7 4.2 10 38.8 492 Example 1-4 223 -- C7 4.4 10 38.2 531 Example 1-5 226 -- A6 4.2 10 95.7 143 Example 1-6 101 -- A6 4.2 10 96.5 138 Example 1-7 259 -- A6 4.3 10 97.2 135 Example 1-8 237 -- A6 4.4 10 95.9 142 Example 1-9 226 -- B1 4.1 10 96.7 127 Example 1- 101 -- B1 4.1 10 96.1 122 10 Example 1- 259 -- B1 4.3 10 95.3 135 11 Example 1- 237 -- B1 4.3 10 97.2 140 12 Example 1- 226 -- A2 4.2 10 94.9 122 13 Example 1- 101 -- A2 4.1 10 95.2 124 14 Example 1- 259 -- A2 4.4 10 96.3 126 15 Example 1- 237 -- A2 4.4 10 95.0 135 16 Example 1- 226 -- C11 4.2 10 96.2 124 17 Example 1- 101 -- C11 4.2 10 96.6 137 18 Example 1- 259 -- C11 4.4 10 95.4 120 19 Example 1- 237 -- C11 4.3 10 97.1 134 20 Comparative 235 -- NPB 4.2 10 28.6 376 Example 1-1 Comparative 241 -- NPB 4.4 10 29.1 381 Example 1-2 Comparative 226 -- NPB 4.1 10 75.2 51 Example 1-3 Comparative 101 -- NPB 4.1 10 74.3 62 Example 1-4 Comparative 259 -- NPB 4.2 10 72.1 47 Example 1-5 Comparative 237 -- NPB 4.3 10 74.9 64 Example 1-6

TABLE-US-00005 TABLE 5 Driving Current First Second Third voltage density Efficiency T.sub.97 compound compound compound (V) (mA/cm.sup.2) (cd/A) (hr) Example 2-1 -- 191A F1 4.4 10 40.1 520 Example 2-2 -- 202A F1 4.3 10 41.2 503 Example 2-3 -- 191A C7 4.1 10 39.7 488 Example 2-4 -- 202A C7 4.2 10 40.5 510 Example 2-5 -- 154A A6 4.3 10 96.5 132 Example 2-6 -- 121A A6 4.2 10 97.7 127 Example 2-7 -- 210A A6 4.4 10 97.6 145 Example 2-8 -- 156A A6 4.2 10 96.8 140 Example 2-9 -- 154A B1 4.3 10 98.7 133 Example 2- -- 121A B1 4.1 10 97.3 138 10 Example 2- -- 210A B1 4.2 10 96.9 145 11 Example 2- -- 156A B1 4.1 10 99.1 142 12 Example 2- -- 154A A2 4.3 10 96.2 129 13 Example 2- -- 121A A2 4.2 10 95.9 121 14 Example 2- -- 210A A2 4.3 10 97.4 140 15 Example 2- -- 156A A2 4.2 10 97.1 128 16 Example 2- -- 154A C11 4.4 10 97.6 133 17 Example 2- -- 121A C11 4.2 10 96.8 136 18 Example 2- -- 210A C11 4.3 10 98.4 141 19 Example 2- -- 156A C11 4.1 10 97.7 144 20 Comparative -- 191A NPB 4.4 10 28.8 362 Example 2-1 Comparative -- 202A NPB 4.3 10 29.4 349 Example 2-2 Comparative -- 154A NPB 4.4 10 78.2 65 Example 2-3 Comparative -- 121A NPB 4.2 10 76.4 71 Example 2-4 Comparative -- 212A NPB 4.3 10 77.1 61 Example 2-5 Comparative -- 156A NPB 4.2 10 75.8 54 Example 2-6

TABLE-US-00006 TABLE 6 Driving Current First Second Third voltage density Efficiency T.sub.97 compound compound compound (V) (mA/cm.sup.2) (cd/A) (hr) Example 3-1 226 172B A6 4.2 10 93.1 172 Example 3-2 119 125B A6 4.4 10 94.2 175 Example 3-3 237 226B A6 4.4 10 94.7 182 Example 3-4 371 190A A6 4.3 10 95.3 167 Example 3-5 306 155A A6 4.3 10 93.8 164 Example 3-6 338 151A A6 4.3 10 93.5 181 Example 3-7 226 172B B1 4.3 10 94.5 179 Example 3-8 119 125B B1 4.5 10 96.4 175 Example 3-9 237 226B B1 4.4 10 94.7 168 Example 3- 374 121A B1 4.2 10 95.9 175 10 Example 3- 306 190A B1 4.3 10 94.6 183 11 Example 3- 338 151A B1 4.2 10 93.5 170 12 Example 3- 226 172B A2 4.1 10 95.1 182 13 Example 3- 119 125B A2 4.3 10 94.5 189 14 Example 3- 237 226B A2 4.4 10 93.8 191 15 Example 3- 374 121A A2 4.3 10 94.2 185 16 Example 3- 306 190A A2 4.2 10 96.1 171 17 Example 3- 338 151A A2 4.1 10 94.7 185 18 Example 3- 226 172B C11 4.1 10 94.6 177 19 Example 3- 119 125B C11 4.4 10 95.1 169 20 Example 3- 237 226B C11 4.3 10 95.4 188 21 Example 3- 237 121A C11 4.3 10 95.8 176 22 Example 3- 374 190A C11 4.2 10 94.2 184 23 Example 3- 338 151A C11 4.2 10 93.9 180 24 Comparative 226 172B NPB 4.3 10 70.6 102 Example 3-1 Comparative 119 125B NPB 4.5 10 72.5 115 Example 3-2 Comparative 237 226B NPB 4.5 10 71.6 121 Example 3-3 Comparative 374 121A NPB 4.4 10 74.7 104 Example 3-4 Comparative 306 190A NPB 4.3 10 73.4 108 Example 3-5 Comparative 338 151A NPB 4.3 10 72.2 116 Example 3-6

[0370] Referring to Tables 4 to 6, it was found that the organic light-emitting devices manufactured in Examples 1-1 to 1-20, 2-1 to 2-20, and 3-1 to 3-24 each exhibited high efficiency and long lifespan characteristics compared with the organic light-emitting devices manufactured in Comparative Examples 1-1 to 1-6, 2-1 to 2-6, and 3-1 to 3-6.

[0371] An organic light-emitting device according to embodiments of the present disclosure may have high efficiency and a long lifespan.

[0372] It should be understood that the example embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment should typically be considered as being available for other similar features or aspects in other example embodiments.

[0373] The use of "may" when describing embodiments of the present disclosure refers to "one or more embodiments of the present disclosure". In addition, as used herein, the terms "use", "using", and "used" may be considered synonymous with the terms "utilize", "utilizing", and "utilized", respectively.

[0374] As used herein, the terms "substantially", "about", and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art.

[0375] Also, any numerical range recited herein is intended to include all subranges of the same numerical precision subsumed within the recited range. For example, a range of "1.0 to 10.0" is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein.

[0376] While one or more example embodiments have been described with reference to the drawing, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims and equivalents thereof.

Claims

1. An organic light-emitting device comprising: a first electrode; a second electrode; and an organic layer comprising an emission layer between the first electrode and the second electrode, the organic layer comprising: at least one compound selected from a first compound and a second compound; in addition to a third compound, wherein the first compound is represented by one selected from Formulae 1-1 and 1-2, the second compound is represented by Formula 2, and the third compound is represented by one selected from Formulae 3-1A and 3-2A: ##STR00182## wherein, in Formulae 1-1, 1-2, 2, 3-1, and 3-2, A.sub.11 to A.sub.13, A.sub.21 to A.sub.24, and A.sub.31 to A.sub.34 are each independently selected from a C.sub.5-C.sub.20 carbocyclic group and a C.sub.1-C.sub.20 heterocyclic group, X.sub.11 is selected from N[(L.sub.11).sub.a11-Ar.sub.11], C(Ar.sub.13)(Ar.sub.15), O, and S, X.sub.12 is selected from N[(L.sub.12).sub.a12-Ar.sub.12], C(Ar.sub.14)(Ar.sub.16), O, and S, X.sub.21 is selected from N[(L.sub.22).sub.a22-Ar.sub.22], C(Ar.sub.23)(Ar.sub.24), O, S, Si(Ar.sub.25)(Ar.sub.26), P[(L.sub.23).sub.a23-Ar.sub.27], B[(L.sub.24).sub.a24-Ar.sub.28], and P(.dbd.O)[(L.sub.25).sub.a25-Ar.sub.29], L.sub.11, L.sub.12, L.sub.21 to L.sub.26, and L.sub.31 to L.sub.35 are each independently selected from a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkylene group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkylene group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenylene group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenylene group, a substituted or unsubstituted C.sub.6-C.sub.60 arylene group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group, a11, a12, a21 to a26, and a31 to a35 are each independently an integer selected from 0 to 5, Ar.sub.11 to Ar.sub.16, Ar.sub.21 to Ar.sub.29, and Ar.sub.31 to Ar.sub.35 are each independently selected from a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5), and --B(Q.sub.6)(Q.sub.7), provided that: in Formula 3-1A, Ar.sub.31 and Ar.sub.32 are both not a substituted or unsubstituted fluorenyl group, in Formula 2, Ar.sub.25 and Ar.sub.26 are optionally linked to each other to form a saturated or unsaturated ring, in Formulae 3-1A and 3-2A, Ar.sub.31 and Ar.sub.32 are optionally linked to each other to form a saturated or unsaturated ring, and in Formula 3-2A, Ar.sub.33 and Ar.sub.34 are optionally linked to each other to form a saturated or unsaturated ring, R.sub.11 to R.sub.13, R.sub.21 to R.sub.24, and R.sub.31 to R.sub.34 are each independently selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C.sub.1-C.sub.60 alkyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.60 alkynyl group, a substituted or unsubstituted C.sub.1-C.sub.60 alkoxy group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkyl group, a substituted or unsubstituted C.sub.3-C.sub.10 cycloalkenyl group, a substituted or unsubstituted C.sub.1-C.sub.10 heterocycloalkenyl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryl group, a substituted or unsubstituted C.sub.6-C.sub.60 aryloxy group, a substituted or unsubstituted C.sub.6-C.sub.60 arylthio group, a substituted or unsubstituted C.sub.1-C.sub.60 heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, --Si(Q.sub.11)(Q.sub.12)(Q.sub.13), --N(Q.sub.14)(Q.sub.15), and --B(Q.sub.16)(Q.sub.17), b11 to b13, b21 to b24, and b31 to b34 are each independently an integer selected from 0 to 8, c1 to c5 are each independently an integer selected from 1 to 3, and at least one substituent of the substituted C.sub.3-C.sub.10 cycloalkylene group, substituted C.sub.1-C.sub.10 heterocycloalkylene group, substituted C.sub.3-C.sub.10 cycloalkenylene group, substituted C.sub.1-C.sub.10 heterocycloalkenylene group, substituted C.sub.6-C.sub.60 arylene group, substituted C.sub.1-C.sub.60 heteroarylene group, substituted divalent non-aromatic condensed polycyclic group, substituted divalent non-aromatic condensed heteropolycyclic group, substituted C.sub.1-C.sub.60 alkyl group, substituted C.sub.2-C.sub.60 alkenyl group, substituted C.sub.2-C.sub.60 alkynyl group, substituted C.sub.1-C.sub.60 alkoxy group, substituted C.sub.3-C.sub.10 cycloalkyl group, substituted C.sub.1-C.sub.10 heterocycloalkyl group, substituted C.sub.3-C.sub.10 cycloalkenyl group, substituted C.sub.1-C.sub.10 heterocycloalkenyl group, substituted C.sub.6-C.sub.60 aryl group, substituted C.sub.6-C.sub.60 aryloxy group, substituted C.sub.6-C.sub.60 arylthio group, substituted C.sub.1-C.sub.60 heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group is selected from the group consisting of: deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group; a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, and a C.sub.1-alkoxy group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --Si(Q.sub.21)(Q.sub.22)(Q.sub.23), --N(Q.sub.24)(Q.sub.25), and --B(Q.sub.26)(Q.sub.27); a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group; a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --Si(Q.sub.31)(Q.sub.32)(Q.sub.33), --N(Q.sub.34)(Q.sub.35), and --B(Q.sub.36)(Q.sub.37), --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), --N(Q.sub.44)(Q.sub.45), and --B(Q.sub.46)(Q.sub.47), wherein Q.sub.1 to Q.sub.7, Q.sub.11 to Q.sub.17, Q.sub.21 to Q.sub.27, Q.sub.31 to Q.sub.37, and Q.sub.41 to Q.sub.47 are each independently selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group; and a C.sub.6-C.sub.60 aryl group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.1-C.sub.60 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, and Q.sub.4 and Q.sub.5 are optionally linked to each other to form a saturated or unsaturated ring.

2. The organic light-emitting device of claim 1, wherein: A.sub.11 to A.sub.13, A.sub.21 to A.sub.24, and A.sub.31 to A.sub.34 are each independently selected from a benzene, a naphthalene, a phenanthrene, an anthracene, a pyridine, a pyrimidine, a quinoline, an isoquinoline, naphthyridine, a quinoxaline, a phthalazine, a quinazoline and a cinnoline.

3. The organic light-emitting device of claim 1, wherein: X.sub.11 is N[(L.sub.11).sub.a11-Ar.sub.11], and X.sub.12 is N[(L.sub.12).sub.a12-Ar.sub.12]; X.sub.11 is N[(L.sub.11).sub.a11-Ar.sub.11], and X.sub.12 is C(Ar.sub.14)(Ar.sub.16); X.sub.11 is N[(L.sub.11).sub.a11-Ar.sub.11], and X.sub.12 is O; or X.sub.11 is N[(L.sub.11).sub.a11-Ar.sub.11], and X.sub.12 is S.

4. The organic light-emitting device of claim 1, wherein: L.sub.11, L.sub.12, and L.sub.21 to L.sub.26 are each independently selected from the group consisting of: a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, a benzofuranylene group, a benzothiophenylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a thiadiazolylene group, an imidazopyridinylene group, an imidazopyrimidinylene group; and a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, an imidazolylene group, a pyrazolylene group, a thiazolylene group, an isothiazolylene group, an oxazolylene group, an isoxazolylene group, a pyridinylene group, a pyrazinylene group, a pyrimidinylene group, a pyridazinylene group, an isoindolylene group, an indolylene group, an indazolylene group, a purinylene group, a quinolinylene group, an isoquinolinylene group, a benzoquinolinylene group, a phthalazinylene group, a naphthyridinylene group, a quinoxalinylene group, a quinazolinylene group, a cinnolinylene group, a carbazolylene group, a phenanthridinylene group, an acridinylene group, a phenanthrolinylene group, a phenazinylene group, a benzimidazolylene group, a benzofuranylene group, a benzothiophenylene group, an isobenzothiazolylene group, a benzoxazolylene group, an isobenzoxazolylene group, a triazolylene group, a tetrazolylene group, an oxadiazolylene group, a triazinylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group, a thiadiazolylene group, an imidazopyridinylene group, and an imidazopyrimidinylene group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, L.sub.31 to L.sub.35 are each independently selected from the group consisting of: a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, a ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, a carbazolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, a dibenzocarbazolylene group; a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an indacenylene group, an acenaphthylene group, a fluorenylene group, a spiro-bifluorenylene group, a benzofluorenylene group, a dibenzofluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, a pentaphenylene group, a hexacenylene group, a pentacenylene group, a rubicenylene group, a coronenylene group, an ovalenylene group, a pyrrolylene group, a thiophenylene group, a furanylene group, a carbazolylene group, a benzofuranylene group, a benzothiophenylene group, a dibenzofuranylene group, a dibenzothiophenylene group, a benzocarbazolylene group, and a dibenzocarbazolylene group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, and a dibenzocarbazolyl group; and a phenylene group substituted with at least one --N(Q.sub.44)(Q.sub.45), wherein Q.sub.44 and Q.sub.45 are each the same as described above.

5. The organic light-emitting device of claim 1, wherein: L.sub.11, L.sub.12 and L.sub.21 to L.sub.26 are each independently selected from groups represented by Formulae 3-1 to 3-34, and L.sub.31 to L.sub.35 are each independently selected from groups represented by Formulae 3-1 to 3-10, 3-26 to 3-28, 3-32, and 3-33: ##STR00183## ##STR00184## ##STR00185## ##STR00186## wherein, in Formulae 3-1 to 3-34, Y.sub.11 is selected from O, S, S(.dbd.O), S(.dbd.O).sub.2, C(Z.sub.3)(Z.sub.4), N(Z.sub.5), and Si(Z.sub.6)(Z.sub.7), Z.sub.1 to Z.sub.7 are each independently selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.2-C.sub.20 alkenyl group, a C.sub.2-C.sub.20 alkynyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, a fluorenyl group, a carbazolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and --N(Q.sub.44)(C).sub.45), and d1 is an integer selected from 1 to 4, d2 is an integer selected from 1 to 3, d3 is an integer selected from 1 to 6, d4 is an integer selected from 1 to 8, d5 is selected from 1 and 2, d6 is an integer selected from 1 to 5, and * and *' each indicate a binding site to a neighboring atom.

6. The organic light-emitting device of claim 1, wherein: Ar.sub.11 to Ar.sub.16 and Ar.sub.21 to Ar.sub.29 are each independently selected from the group consisting of: a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group; a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, a thiadiazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, a dibenzosilolyl group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), and --N(Q.sub.44)(Q.sub.45), and Ar.sub.31 to Ar.sub.35 are each independently selected from the group consisting of: a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group; a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenyl group, a rubicenyl group, a coronenyl group, an ovalenyl group, a thiophenyl group, a furanyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), and --N(Q.sub.44)(Q.sub.45), wherein Q.sub.1 to Q.sub.5 and Q.sub.41 to Q.sub.45 are each independently selected from the group consisting of: a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group; a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group; and a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

7. The organic light-emitting device of claim 1, wherein: Ar.sub.11 to Ar.sub.16 and Ar.sub.21 to Ar.sub.29 are each independently selected from the group consisting of: a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group; --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and groups represented by Formulae 5-1 to 5-49 and 7-1 to 7-10, and Ar.sub.31 to Ar.sub.35 are each independently selected from the group consisting of: a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group; --Si(Q.sub.1)(Q.sub.2)(Q.sub.3), --N(Q.sub.4)(Q.sub.5); and groups represented by Formulae 7-1 to 7-10: ##STR00187## ##STR00188## ##STR00189## ##STR00190## ##STR00191## ##STR00192## wherein, in Formulae 5-1 to 5-29, Z.sub.41 to Z.sub.43 are each independently selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), --N(Q.sub.44)(Q.sub.45), a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, an imidazopyridinyl group and an imidazopyrimidinyl group, f1 is an integer selected from 1 to 4, f2 is an integer selected from 1 to 3, f3 is an integer selected from 1 and 2, f4 is an integer selected from 1 to 6, and f5 is an integer selected from 1 to 5; in Formulae 7-1 to 7-10, Y.sub.31 and Y.sub.32 are each independently selected from a single bond, O, S, C(Z.sub.34)(Z.sub.35), N(Z.sub.36), and Si(Z.sub.37)(Z.sub.38), provided that Y.sub.31 and Y.sub.32 are not both single bonds; Z.sub.31 to Z.sub.38 are each independently selected from hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, --Si(Q.sub.41)(Q.sub.42)(Q.sub.43), --N(Q.sub.44)(Q.sub.45); a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, e1 is an integer selected from 1 to 5, e2 is an integer selected from 1 to 7, e3 is an integer selected from 1 to 3, e4 is an integer selected from 1 to 4, and * and *' each indicate a binding site to a neighboring atom, wherein Q.sub.1 to Q.sub.5 and Q.sub.41 to Q.sub.45 are each independently selected from the group consisting of: a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group; a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a carbazolyl group; and a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and a carbazolyl group, each substituted with at least one selected from a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

8. The organic light-emitting device of claim 1, wherein: R.sub.11 to R.sub.13 and R.sub.21 to R.sub.24 are each independently selected from the group consisting of: hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group; a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, an indolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group; a phenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, a chrysenyl group, an indolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, and a dibenzocarbazolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group; and --Si(Q.sub.11)(Q.sub.12)(Q.sub.13) and --N(Q.sub.14)(Q.sub.15), and R.sub.31 to R.sub.34 are each independently selected from the group consisting of: hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkoxy group; a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, a dibenzosilolyl group; and a phenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group, wherein Q.sub.11 to Q.sub.15 are each independently selected from a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group.

9. The organic light-emitting device of claim 1, wherein: the first compound is represented by one selected from Formulae 1-11 to 1-15 and 1-21 to 1-23: ##STR00193## ##STR00194## wherein, in Formulae 1-11 to 1-15 and 1-21 to 1-23, A.sub.11, A.sub.13, X.sub.11, X.sub.12, R.sub.11 to R.sub.13, and b11 to b13 are each the same as described above.

10. The organic light-emitting device of claim 1, wherein: the second compound is represented by Formula 2-1: ##STR00195## wherein, in Formula 2-1, A.sub.21, A.sub.24, X.sub.21, L.sub.21, L.sub.26, a21, a26, Ar.sub.21, R.sub.21 to R.sub.24, b21, and b24 are each the same as described above, and b22 and b23 are each independently an integer selected from 0 to 3.

11. The organic light-emitting device of claim 1, wherein: the second compound is represented by one selected from Formulae 2-11 to 2-15: ##STR00196## wherein, in Formulae 2-11 to 2-15, X.sub.21, L.sub.21, L.sub.26, a21, a26, Ar.sub.21, R.sub.21 to R.sub.24, b21, and b24 are each the same as described above, and b22 and b23 are each independently an integer selected from 0 to 3.

12. The organic light-emitting device of claim 1, wherein: the third compound is represented by one selected from Formulae 3A to 3C: ##STR00197## wherein, in Formulae 3A to 3C, A.sub.31 to A.sub.34, L.sub.31, L.sub.32, L.sub.35, a31, a32, a35, Ar.sub.31 to Ar.sub.35, c1, c2, c5, R.sub.31 to R.sub.34, b31 to b34, Q.sub.4, and Q.sub.5 are each the same as described above.

13. The organic light-emitting device of claim 1, wherein: the third compound is represented by one selected from Formulae 3A(1), 3A(2), 3B(1) to 3B(3), and 3C(1): ##STR00198## ##STR00199## wherein, in Formulae 3A(1), 3A(2), 3B(1) to 3B(3), and 3C(1), L.sub.35, a31, a35, Ar.sub.31 to Ar.sub.35, c1, c5, R.sub.31 to R.sub.34, Q.sub.4, and Q.sub.5 are each the same as described above, b31 and b33 are each independently an integer selected from 0 to 4, and b32 and b34 are each independently an integer selected from 0 to 3, d1 may be an integer selected from 0 to 4, Z.sub.1 is selected from hydrogen and --N(Q.sub.44)(Q.sub.45), and Q.sub.44 and Q.sub.45 are each the same as described above, Z.sub.31 to Z.sub.34 are each independently selected from the group consisting of: hydrogen, deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.10 alkyl group, a C.sub.1-C.sub.10 alkoxy group; a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a spiro-fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group, a perylenyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, and a dibenzosilolyl group, and e4 is an integer selected from 0 to 4.

14. The organic light-emitting device of claim 1, wherein: the first compound is selected from Compounds 100 to 272 and 301 to 374, the second compound is selected from Compounds 101A to 212A and 101B to 230B, and the third compound is selected from Compounds A1 to A27, B1 to B25, C1 to C16, D1 to D9, E1 to E10, and F1 to F32: ##STR00200## ##STR00201## ##STR00202## ##STR00203## ##STR00204## ##STR00205## ##STR00206## ##STR00207## ##STR00208## ##STR00209## ##STR00210## ##STR00211## ##STR00212## ##STR00213## ##STR00214## ##STR00215## ##STR00216## ##STR00217## ##STR00218## ##STR00219## ##STR00220## ##STR00221## ##STR00222## ##STR00223## ##STR00224## ##STR00225## ##STR00226## ##STR00227## ##STR00228## ##STR00229## ##STR00230## ##STR00231## ##STR00232## ##STR00233## ##STR00234## ##STR00235## ##STR00236## ##STR00237## ##STR00238## ##STR00239## ##STR00240## ##STR00241## ##STR00242## ##STR00243## ##STR00244## ##STR00245## ##STR00246## ##STR00247## ##STR00248## ##STR00249## ##STR00250## ##STR00251## ##STR00252## ##STR00253## ##STR00254## ##STR00255## ##STR00256## ##STR00257## ##STR00258## ##STR00259## ##STR00260## ##STR00261## ##STR00262## ##STR00263## ##STR00264## ##STR00265## ##STR00266## ##STR00267## ##STR00268## ##STR00269## ##STR00270## ##STR00271## ##STR00272## ##STR00273## ##STR00274## ##STR00275## ##STR00276## ##STR00277## ##STR00278## ##STR00279## ##STR00280## ##STR00281## ##STR00282## ##STR00283## ##STR00284## ##STR00285## ##STR00286## ##STR00287## ##STR00288## ##STR00289## ##STR00290## ##STR00291## ##STR00292## ##STR00293## ##STR00294## ##STR00295## ##STR00296## ##STR00297## ##STR00298## ##STR00299## ##STR00300## ##STR00301## ##STR00302## ##STR00303## ##STR00304## ##STR00305##

15. The organic light-emitting device of claim 1, wherein: the emission layer further comprises an organometallic complex represented by Formula 401: ##STR00306## wherein, in Formula 401, M is selected from iridium (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm), X.sub.401 to X.sub.404 are each independently selected from nitrogen and carbon, rings A.sub.401 and A.sub.402 are each independently selected from a substituted or unsubstituted benzene, a substituted or unsubstituted naphthalene, a substituted or unsubstituted fluorene, a substituted or unsubstituted spiro-fluorene, a substituted or unsubstituted indene, a substituted or unsubstituted pyrrole, a substituted or unsubstituted thiophene, a substituted or unsubstituted furan, a substituted or unsubstituted imidazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted thiazole, a substituted or unsubstituted isothiazole, a substituted or unsubstituted oxazole, a substituted or unsubstituted isoxazole, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyrazine, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted pyridazine, a substituted or unsubstituted quinoline, a substituted or unsubstituted isoquinoline, a substituted or unsubstituted benzoquinoline, a substituted or unsubstituted quinoxaline, a substituted or unsubstituted quinazoline, a substituted or unsubstituted carbazole, a substituted or unsubstituted benzimidazole, a substituted or unsubstituted benzofuran, a substituted or unsubstituted benzothiophene, a substituted or unsubstituted isobenzothiophene, a substituted or unsubstituted benzoxazole, a substituted or unsubstituted isobenzoxazole, a substituted or unsubstituted triazole, a substituted or unsubstituted oxadiazole, a substituted or unsubstituted triazine, a substituted or unsubstituted dibenzofuran, and a substituted or unsubstituted dibenzothiophene, at least one substituent of the substituted benzene, substituted naphthalene, substituted fluorene, substituted spiro-fluorene, substituted indene, substituted pyrrole, substituted thiophene, substituted furan, substituted imidazole, substituted pyrazole, substituted thiazole, substituted isothiazole, substituted oxazole, substituted isoxazole, substituted pyridine, substituted pyrazine, substituted pyrimidine, substituted pyridazine, substituted quinoline, substituted isoquinoline, substituted benzoquinoline, substituted quinoxaline, substituted quinazoline, substituted carbazole, substituted benzimidazole, substituted benzofuran, substituted benzothiophene, substituted isobenzothiophene, substituted benzoxazole, substituted isobenzoxazole, substituted triazole, substituted oxadiazole, substituted triazine, substituted dibenzofuran and substituted dibenzothiophene is selected from the group consisting of: deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group; a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, and a C.sub.1-C.sub.60 alkoxy group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group (non-aromatic condensed polycyclic group), a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --N(Q.sub.401)(Q.sub.402), --Si(Q.sub.403)(Q.sub.404)(Q.sub.405), and --B(Q.sub.406)(Q.sub.407); a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group; a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60 aryloxy group, a C.sub.6-C.sub.60 arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, and a terphenyl group, each substituted with at least one selected from deuterium, --F, --Cl, --Br, --I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C.sub.1-C.sub.60 alkyl group, a C.sub.2-C.sub.60 alkenyl group, a C.sub.2-C.sub.60 alkynyl group, a C.sub.1-C.sub.60 alkoxy group, a C.sub.3-C.sub.10 cycloalkyl group, a C.sub.1-C.sub.10 heterocycloalkyl group, a C.sub.3-C.sub.10 cycloalkenyl group, a C.sub.1-C.sub.10 heterocycloalkenyl group, a C.sub.6-C.sub.60 aryl group, a C.sub.6-C.sub.60aryloxy group, a C.sub.6-C.sub.60arylthio group, a C.sub.1-C.sub.60 heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, a biphenyl group, a terphenyl group, --N(Q.sub.411)(Q.sub.412), --Si(Q.sub.413)(Q.sub.414)(Q.sub.415), and --B(Q.sub.416)(Q.sub.417); --N(Q.sub.421)(Q.sub.422), --Si(Q.sub.423)(Q.sub.424)(Q.sub.425), and --B(Q.sub.426)(Q.sub.427), L.sub.401 is an organic ligand, xc1 is selected from 1, 2, and 3, xc2 is selected from 0, 1, 2, and 3, and Q.sub.401 to Q.sub.407, Q.sub.411 to Q.sub.417, and Q.sub.421 to Q.sub.427 are each the same as described herein in connection with Q.sub.1.

16. The organic light-emitting device of claim 1, wherein: the emission layer comprises at least one compound selected from the first compound and the second compound, and the organic layer further comprises a hole transport region between the first electrode and the emission layer, the hole transport region comprising an emission auxiliary layer, wherein the hole transport region comprises the third compound.

17. The organic light-emitting device of claim 16, wherein the emission auxiliary layer directly contacts the emission layer.

18. The organic light-emitting device of claim 16, wherein: the emission layer comprises the first compound and the emission auxiliary layer comprises the third compound; or the emission layer comprises the second compound and the emission auxiliary layer comprises the third compound.

19. The organic light-emitting device of claim 16, wherein: the emission layer comprises a first host selected from the first compound and a second host selected from the second compound, and the emission auxiliary layer comprises the third compound; the emission layer comprises a third host and a fourth host, each selected from the first compound, the third host and the fourth host are different from each other, and the emission auxiliary layer comprises the third compound; or the emission layer comprises a fifth host and a sixth host, each selected from the second compound, the fifth host and the sixth host are different from each other, and the emission auxiliary layer comprises the third compound.

20. The organic light-emitting device of claim 14, wherein: the first compound is selected from Compounds 100 to 272, and the second compound is selected from Compounds 101B to 230B; or the first compound is selected from Compounds 301 to 374, and the second compound is selected from Compounds 101A to 212A.

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